Modified colored pigments and ink jet inks, inks, and coatings containing modified colored pigments

ABSTRACT

A modified colored pigment is described which comprises colored pigment having attached at least one organic group. The organic group comprises a) at least one aromatic group or a C 1  -C 12  alkyl group and b) at least one ionic group, at least one ionizable group, or a mixture of an ionic group and an ionizable group. The aromatic group or the C 1  -C 12  alkyl group of the organic group is directly attached to the pigment and the organic group is present at a treatment level of from about 0.10 to about 4.0 micromoles/m 2  of the pigment used based on nitrogen surface area of the pigment. Also described are aqueous and non-aqueous inks and coatings and ink jet ink compositions containing the modified colored pigment. A method to increase the flow of an ink is also disclosed as well as a method to improve the waterfastness of a print imaged by an ink composition. Also, other ink jet ink compositions are described which comprise an aqueous or non-aqueous vehicle and a colored pigment having attached an organic group having the formula: Ar--R 1  (I) or Ar&#39;R 3  R 2  (II) wherein Ar is an aromatic group and Ar&#39; is an aromatic group.

This application is a continuation-in-part of U.S. patent applicationSer. No. 08/663,707, filed Jun. 14, 1996, now U.S. Pat. No. 5,707,432,and Ser. No. 08/783,411, filed Jan. 14, 1997, now U.S. Pat. No.5,803,959, which are incorporated in their entirety by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to modified colored pigments, such as modifiedcarbon products, and ink jet inks, inks and coatings which containmodified colored pigments. The present invention is further directed toink compositions and, more particularly, to aqueous ink compositionssuitable for imaging applications, such as ink jet printing processes.

2. Discussion of the Related Art

Presently, predominant black pigments are carbon blacks which can beused as colorants either in dry, powdered form, a flushed paste, or aliquid dispersion form depending upon the method to apply the pigment tothe substrate and the substrate requirements. Generally, physical andsurface properties of the colorant influences the hue, permanency, bulk,opacity, gloss, rheology, end use, and print quality.

There are various classifications of inks used presently. Thesecategories include printing inks, ultraviolet cure inks, ball-pointinks, and stamp pad or marking inks. Generally, inks can be applied byletter press, lithographic, flexographic, gravure, silk screen, stencil,duplicating, and electrostatic. Inks thus can be found in such end usesas news, publication, commercial, folding carton, book, corrugated box,paper bag, wrapper, label, metal container, plastic container, plasticfilm, foil, laminating, food insert, sanitary paper, textile and thelike. McGraw-Hill's Encyclopedia of Science and Technology, Vol. 7, pgs.159-164, provides further details of the types of inks available andtheir uses, all of which is incorporated herein by reference.

Coatings can contain pigments as well and are used for decorative,protective, and functional treatments of many kinds of surfaces. Thesesurfaces include, coils, metals, appliances, furniture, hardboard,lumber and plywood, marine, maintenance, automobile, cans, andpaperboard. Some coatings, such as those on undersea pipelines, are forprotective purposes. Others, such as exterior automobile coatings,fulfill both decorative and protective functions. Still others providefriction control on boat decks or car seats. Some coatings control thefouling of ship bottoms, others protect food and beverages in cans.Silicon chips, printed circuit panels, coatings on waveguide fibers forsignal transmission, and magnetic coatings on video tapes and computerdisks are among many so-called hi-tech applications for coatings.

Categories of aqueous vehicles for aqueous inks and coatings includethose in which the binder is soluble in water, those in which it iscolloidally dispersed, and those in which it is emulsified to form alatex. The combination of binder and volatile liquid is called thevehicle which may be a solution or a dispersion of fine binder particlesin a non-solvent. Pigments are finely divided, insoluble, solidparticles dispersed in the coating vehicle and distributed throughoutthe binder in the final film. Surfactants or polymers can be used aspigment dispersants. The components and manufacturing of aqueouscoatings are further discussed in the Concise Encyclopedia of Polymers,Science and Engineering, pgs. 160-171 (1990), which is incorporatedherein by reference.

Non-aqueous inks and coatings are used for many applications in whichaqueous vehicles are not suitable. For instance, inks which are to beprinted on hydrophobic, non-porous substrates such as metal, glass, orplastics must be fast-drying. Therefore, solvents such as ketones,esters, alcohols, or hydrocarbons are often used instead of water. Suchsolvent-based inks are used widely for industrial labeling of cardboardboxes and various metal or plastic containers and components. Specificexamples include news ink compositions and web off-set gloss heat-setink compositions.

Inks and coatings are also required to be water resistant in certainsituations. In such instances, water-resistant resins can be dissolvedin non-aqueous solvents of ink and coating formulations to provide thedesired water resistance upon drying. A primary use of such non-aqueouscoatings is on metal and plastic automotive parts.

Ink jet printing is a non-impact process wherein droplets of ink areproduced and deposited on a substrate such as paper, transparent film,polymer sheet, or textile material in response to an electronic signal.Ink jet printing systems are typically classified by two known types:continuous stream or drop-on-demand.

Ink compositions which are useful in imaging applications, such as inkjet ink printing systems, are well known and generally contain watersoluble dyes. Although dye-based inks are suitable for their intendedpurposes, dyes have several disadvantages when used in ink jet inks. Forexamples, dyes, being water-soluble in a water/organic mixture, maydissolve and run when exposed to moisture or water. Dye images mayfurther smear or rub off on contact with felt pen markers or upon beingrubbed or touched by finger. Dyes also exhibit poor light stability whenexposed to visible, ultraviolet light, or sunlight.

Pigments are also known as colorants in ink compositions but have notreceived a wide degree of acceptance in ink jet ink systems, forexample, because of problems associated with the performance andreliability of the composition, i.e., print properties, stability,latency, and the like.

As a result, although known compositions are suitable for their intendedpurpose, a need remains for improved ink compositions, especially foruse in the ink jet printers, which overcome the problems typicallyassociated with current dye-based and pigment systems. In addition,there is a need for improved ink compositions providing good printproperties and generating printed images having improved waterfastness.

SUMMARY OF THE INVENTION

The present invention relates to a modified colored pigment, such as amodified carbon product, comprising a pigment, like carbon black, havingattached at least one organic group. The organic group comprises a) atleast one aromatic group or a C₁ -C₁₂ alkyl group and b) at least oneionic group, at least one ionizable group, or a mixture of an ionicgroup and an ionizable group. The aromatic group or the C₁ -C₁₂ alkylgroup is directly attached to the colored pigment (e.g. carbon black)and the organic group is present at a treatment level of from about 0.10to about 4.0 micromoles/m² colored pigment.

The present invention also relates to a coating or ink composition,aqueous or non-aqueous, comprising the above-described modified coloredpigment (e.g. modified carbon black product). The present invention inaddition relates to ink jet ink compositions comprising theabove-described modified colored pigment (e.g. modified carbon blackproduct).

In addition, the present invention relates to an ink jet ink compositioncomprising an aqueous or nonaqueous vehicle and a colored pigment havingattached an organic group having the formula: Ar--R¹ (I) or Ar'R³ R²(II) wherein Ar is an aromatic group and Ar' is an aromatic group. Asshown in formula (I), Ar is substituted with at least one group R¹. Asshown in formula (II), Ar' is substituted with at least one group R² andat least one group R³. R¹ is an aromatic or aliphatic group containing ahydrophobic group and at least one hydrophilic group. R² is ahydrophilic group and R³ is an aromatic or aliphatic group containing ahydrophobic group. The organic group is present at a treatment level offrom about 0.10 micromoles/m² colored pigment to about 5.0 micromoles/m²colored pigment, and the image generated from the ink jet inkcomposition is waterfast. The present invention also relates to methodsto improve the waterfastness of an image generated by an ink jet inkcomposition by introducing the above-described modified colored pigmentinto an ink jet ink composition.

The present invention further relates to a non-aqueous coating or inkcomposition comprising a modified colored pigment (e.g. modified carbonblack product) and a non-aqueous solvent. The modified colored pigment(e.g. modified carbon black product) comprises colored pigment (e.g.,carbon black) having attached at least one organic group wherein theorganic group comprises a) at least one aromatic group or a C₁ -C₁₂alkyl group and b) at least one ionic group, at least one ionizablegroup, or a mixture of an ionic group and an ionizable group. Thearomatic group or the C₁ -C₁₂ alkyl group is directly attached to thecolored pigment (e.g., carbon black) and there is no limit on the amountof organic group that can be present.

Colored pigment, as used herein, is any pigment which can be modifiedwith the attachment of at least one organic group. Examples include, butare not limited to, carbon black, and colored pigments other thancarbon, having no primary amines, and preferably, at least one aromaticring in its repeating structure or at its surface to promote themodification of the organic group to the surface of the pigment. A widerange of conventional colored pigments may be used in the presentinvention provided that such pigments do not possess a primary amine.The colored pigment can be blue, brown, cyan, green, violet, magenta,red, yellow, as well as mixtures thereof. Suitable classes of coloredpigments include, for example, anthraquinones, phthalocyanine blues,phthalocyanine greens, diazos, monoazos, pyranthrones, perylenes,heterocyclic yellows, quinacridones, and (thio)indigoids. Representativeexamples of phthalocyanine blues include copper phthalocyanine blue andderivatives thereof (Pigment Blue 15). Representative examples ofquinacridones include Pigment Orange 48, Pigment Orange 49, Pigment Red122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207,Pigment Red 209, Pigment Violet 19 and Pigment Violet 42. Representativeexamples of anthraquinones include Pigment Red 43, Pigment Red 194(Perinone Red), Pigment Red 216 (Brominated Pyrathrone Red) and PigmentRed 226 (Pyranthrone Red). Representative examples of perylenes includePigment Red 123 (Vermillion), Pigment Red 149 (Scarlet), Pigment Red 179(Maroon), Pigment Red 190 (Red), Pigment Violet, Pigment Red 189 (YellowShade Red) and Pigment Red 224. Representative examples of thioindigoidsinclude Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181,Pigment Red 198, Pigment Violet 36, and Pigment Violet 38.Representative examples of heterocyclic yellow include Pigment Yellow117 and Pigment Yellow 138. Examples of other suitable colored pigmentsare described in Colour Index, 3rd edition (The Society of Dyers andCikiyrusts, 1982), incorporated herein by reference.

Carbon, as used herein, may be of the crystalline or amorphous type.Examples include, but are not limited to, graphite, carbon black, carbonfiber, vitreous carbon, and activated charcoal or activated carbon.Finely divided forms of the above are preferred. Also, it is possible toutilize mixtures of different colored pigments including mixtures ofdifferent carbon blacks.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The modified colored pigment (e.g. modified carbon black product) of thepresent invention comprises colored pigment (e.g. carbon black) havingattached thereto at least one organic group. This organic groupcomprises a) at least one aromatic group or a C₁ -C₁₂ alkyl group and b)at least one ionic group, at least one ionizable group, or a mixture ofan ionic group and an ionizable group. The aromatic group or the C₁ -C₁₂alkyl group of the organic group is directly attached to the coloredpigment (e.g. carbon black). Further, the organic group is present at atreatment level of from about 0.10 to about 4.0 micromoles/m² coloredpigment. Treatment level, as used herein, is the amount of organic groupadded to the pigment during the process to form the modified coloredpigment. The amount added may be more than the amount of organic groupactually attached onto the pigment.

The colored pigment is any pigment which can be modified with theattachment of at least one organic group. Examples include, but are notlimited to, carbon black, and colored pigments other than carbon havingno primary amines and, preferably, at least one aromatic ring in itsrepeating structure or at its surface to promote the modification of theorganic group to the surface of the pigment. A wide range ofconventional colored pigments may be used in the present inventionprovided that such pigments do not possess a primary amine. The coloredpigment can be blue, brown, cyan, green, violet, magenta, red, yellow,as well as mixtures thereof. Suitable classes of colored pigmentsinclude, for example, anthraquinones, phthalocyanine blues,phthalocyanine greens, diazos, monoazos, pyranthrones, perylenes,heterocyclic yellows, quinacridones, and (thio)indigoids. Representativeexamples of phthalocyanine blues include copper phthalocyanine blue andderivatives thereof (Pigment Blue 15). Representative examples ofquinacridones include Pigment Orange 48, Pigment Orange 49, Pigment Red122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207,Pigment Red 209, Pigment Violet 19 and Pigment Violet 42. Representativeexamples of anthraquinones include Pigment Red 43, Pigment Red 194(Perinone Red), Pigment Red 216 (Brominated Pyrathrone Red) and PigmentRed 226 (Pyranthrone Red). Representative examples of perylenes includePigment Red 123 (Vermillion), Pigment Red 149 (Scarlet), Pigment Red 179(Maroon), Pigment Red 190 (Red), Pigment Violet, Pigment Red 189 (YellowShade Red) and Pigment Red 224. Representative examples of thioindigoidsinclude Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181,Pigment Red 198, Pigment Violet 36, and Pigment Violet 38.Representative examples of heterocyclic yellow include Pigment Yellow117 and Pigment Yellow 138. Examples of other suitable colored pigmentsare described in Colour Index, 3rd edition (The Society of Dyers andCikiyrusts, 1982). The carbon may be of the crystalline or amorphoustype. Examples include, but are not limited to, graphite, carbon black,vitreous carbon, activated charcoal, carbon fiber, activated carbon, andmixtures thereof. Finely divided forms of the above are preferred. Also,it is possible to utilize mixtures of different colored pigments,including mixtures of different carbons.

The modified colored pigments (e.g. modified carbon black products) maybe prepared preferably by reacting a colored pigment, such as carbonblack, with a diazonium salt in a liquid reaction medium to attach atleast one organic group to the surface of the colored pigment. Thediazonium salt may contain the organic group to be attached to thecolored pigment. A diazonium salt is an organic compound having one ormore diazonium groups. Reaction media include polar media. Preferredreaction media include water, any medium containing water, and anymedium containing alcohol. Water is the most preferred medium. Examplesof modified carbon products, wherein the carbon is carbon black, andvarious preferred methods for their preparation are described in U.S.patent application Ser. No. 08/356,660 entitled "Reaction of CarbonBlack with Diazonium Salts, Resultant Carbon Black Products and TheirUses," filed Dec. 15, 1994 and its continuation-in-part application,U.S. patent application Ser. No. 08/572,525, filed Dec. 14, 1995, bothof which are incorporated herein by reference. Examples of modifiedcarbon products, wherein the carbon is not carbon black, and variouspreferred methods for their preparation are described in U.S. Pat. No.5,554,739, WO 96/18696 and WO 96/18688, all incorporated herein byreference.

In the preferred preparation of the above modified colored pigments,(e.g., modified carbon products), the diazonium salt need only besufficiently stable to allow reaction with the colored pigments. Thus,that reaction can be carried out with some diazonium salts otherwiseconsidered to be unstable and subject to decomposition. Somedecomposition processes may compete with the reaction between thecolored pigment, such as carbon and the diazonium salt and may reducethe total number of organic groups attached to the colored pigment(e.g., carbon black). Further, the reaction may be carried out atelevated temperatures where many diazonium salts may be susceptible todecomposition. Elevated temperatures may also advantageously increasethe solubility of the diazonium salt in the reaction medium and improveits handling during the process. However, elevated temperatures mayresult in some loss of the diazonium salt due to other decompositionprocesses. The diazonium salts may be prepared in situ. It is preferredthat the modified colored pigments (e.g. modified carbon products) ofthe present invention contain no by-products or unattached salts.

In the preferred process of preparation, a colored pigment, such ascarbon black, can be reacted with a diazonium salt when present as adilute, easily stirred, aqueous slurry, or in the presence of the properamount of water for carbon black pellet formation. If desired, carbonblack pellets may be formed utilizing a conventional pelletizingtechnology. Other colored pigments, such as other carbons, can besimilarly reacted with the diazonium salt. In addition, when modifiedcolored pigments utilizing carbon other than carbon black or otherpigments are, for instance, used in non-aqueous inks and coatings, thecarbon or other pigment should preferably be ground to a fine particlesize before reaction with the diazonium salt in the preferred process toprevent unwanted precipitation of the modified colored pigment in theinks and coatings. In addition, when modified colored pigments utilizingcarbon other than carbon black or other pigments are used in ink jetinks, the carbon or other pigment should preferably be ground to a fineparticle size before or after the reaction with the diazonium salt inthe preferred process to prevent unwanted sedimentation in the ink. Anadditional means of stabilization of the particles may be necessary inink jet inks when the amounts of organic groups on the pigment are notsufficient to provide colloidal stability. One such means can be the useof a dispersant.

For purposes of one embodiment of the present invention, the amount oforganic group attached to the colored pigment (e.g. carbon black) isimportant for purposes of the subsequent use of the modified coloredpigment in such applications as ink jet ink compositions, coatingformulations, and ink systems. In particular, the levels should be of alow level. In other words, the treatment levels of organic group may befrom about 0.10 to about 4.0 micromoles/m² of the colored pigment (e.g.carbon black) used, preferably from about 1.5 to about 3.0 micromoles/m²based on nitrogen surface area of the colored pigment.

It was commonly believed that the higher the amount of organic groupattached to the carbon, the better the properties. However, in certainsituations, attaching low levels of organic groups to colored pigments,such as carbon black, results in better properties. These betterproperties have been seen, for instance, with the use of the modifiedcolored pigments, such as modified carbon products, of the presentinvention in non-aqueous applications such as non-aqueous ink andcoating systems including non-aqueous gloss ink systems and non-aqueouscoating formulations. When the modified colored pigments, such as themodified carbon products, of the present invention have been used inthese systems and formulations, improved jetness, blue undertone, andgloss have been achieved and in certain situations, the rheology of theink, as measured by the Laray viscosity, spreadometer values, andvertical glass plate flow properties have been modified. In some inkformulations, flow was increased considerably over that of untreatedcarbon products. In addition, in some ink formulations, such as ink jetink, improved waterfastness of the printed image was achieved.

As stated earlier, in one embodiment, the organic group comprises anaromatic group or a C₁ -C₁₂ alkyl group. The aromatic group includes,but is not limited to, unsaturated cyclic hydrocarbons containing one ormore rings. The aromatic group may be substituted or unsubstituted.Aromatic groups include aryl groups (for example, phenyl, naphthyl,anthracenyl, and the like), and heteroaryl groups (imidazolyl,pyrazolyl, pyridinyl, thienyl, thiazolyl, furyl, triazinyl, indolyl, andthe like). The C₁ -C₁₂ alkyl group may be branched or unbranched and ispreferably ethyl.

An ionizable group is one which is capable of forming an ionic group inthe medium of use. The ionic group may be an anionic group or a cationicgroup and the ionizable group may form an anion or a cation.

Ionizable functional groups forming anions include, for example, acidicgroups or salts of acidic groups. The organic groups, therefore, caninclude groups derived from organic acids. Preferably, when the organicgroup contains an ionizable group forming an anion, the organic grouphas a) an aromatic group or a C₁ -C₁₂ alkyl group and b) at least oneacidic group having a pKa of less than 11, or at least one salt of anacidic group having a pKa of less than 11, or a mixture of at least oneacidic group having a pKa of less than 11 and at least one salt of anacidic group having a pKa of less than 11. The pKa of the acidic grouprefers to the pKa of the organic group as a whole, not just the acidicsubstituent. More preferably, the pKa is less than 10 and mostpreferably less than 9. The aromatic group may be further substituted orunsubstituted, for example, with alkyl groups. More preferably, theorganic group is a phenyl or a naphthyl group and the acidic group is asulfonic acid group, a sulfinic acid group, a phosphonic acid group, ora carboxylic acid group. The naphthyl group may be mono-substituted withan acidic group on either ring. The naphthyl group may also besubstituted with two or more acidic groups, with the acidic groups onthe same or different rings. Examples of ionic or ionizable groupsinclude --COOH, --SO₃ H and --PO₃ H₂, --SO₂ NHCOR, and their salts, forexample --COONa, --COOK, --COO⁻ NR₄ ⁺, --SO₃ Na, --HPO₃ Na, --SO₃ ⁻ NR₄⁺, and PO₃ Na₂, where R is a saturated or unsaturated alkyl or phenylgroup. Particularly preferred ionizable substituents are --COOH and--SO₃ H and their sodium and potassium salts.

Accordingly, it is preferred that the colored pigment, such as carbon,is treated with aryl diazonium salts containing at least one acidicfunctional group. Examples of aryl diazonium salts include, but are notlimited to, those prepared from sulfanilic acid, 4-aminobenzoic acid,4-amino salicylic acid, 7-amino-4-hydroxy-2-naphthlenesulfonic acid,aminophenylboronic acid, aminophenylphosphonic acid, 4-aminophthalicacid, 2-amino-1-naphthalenesulfonic acid, 5-amino-2-naphthalenesulfonicacid, and metanilic acid.

The organic group can be a substituted or unsubstituted sulfophenylgroup or a salt thereof; a substituted or unsubstituted(polysulfo)phenyl group or a salt thereof; a substituted orunsubstituted sulfonaphthyl group or a salt thereof; or a substituted orunsubstituted (polysulfo)naphthyl group or a salt thereof. One exampleof a sulfophenyl group is hydroxysulfophenyl group or a salt thereof.

Specific organic groups having an ionizable functional group forming ananion are p-sulfophenyl and 4-hydroxy-3-sulfophenyl.

Amines represent examples of ionizable functional groups that formcationic groups and can be attached to the same organic groups asdiscussed above for the ionizable groups which form anions. For example,amines may be protonated to form ammonium groups in acidic media.Preferably, an organic group having an amine substituent has a pKb ofless than 5. Quaternary ammonium groups (--NR₃ ⁺) and quaternaryphosphonium groups (--PR₃ ⁺) also represent examples of cationic groupsand can be attached to the same organic groups as discussed above forthe ionizable groups which form anions. Preferably, the organic groupcontains an aromatic group such as a phenyl or a naphthyl group and aquaternary ammonium or a quaternary phosphonium group. Quaternizedcyclic amines, and quaternized aromatic amines, can also be used as theorganic group. Thus, N-substituted pyridinium compounds, such asN-methyl-pyridyl, can be used in this regard. Examples of organic groupsinclude, but are not limited to, 3-C₅ H₄ N(C₂ H₅)⁺ X⁻, C₆ H₄ NC₅ H₅ ⁺X⁻, C₆ H₄ COCH₂ N(CH)₃)₃ ⁺ X⁻, C₆ H₄ COCH₂ (NC₅ H₅)⁺ X⁻, 3-C₅ H₄ N(CH₃)⁺X⁻, C₆ H₄ N(CH₃)₃ ⁺ X⁻, and C₆ H₄ CH₂ N(CH₃)₃ ⁺ X⁻, wherein X⁻ is ahalide or an anion derived from a mineral or organic acid. Otherexamples include pC₆ H₄ --SO₃ ⁻ Na⁺, pC₆ H₄ --CO₂ ⁻ Na⁺, and C₅ H₄ N⁺ C₆H₅ (NO₃)⁻.

Additional optional functional groups which may be present on theorganic group include, but are not limited to, R, OR, COR, COOR, OCOR,halogen, CN, NR₂, SO₂ NR(COR), SO₂ NR₂, NR(COR), CONR₂, NO₂, SO₃ M, SO₃NR₄, and N═NR'. R is independently hydrogen, C₁ -C₂₀ substituted orunsubstituted alkyl (branched or unbranched), C₃ -C₂₀ substituted orunsubstituted alkenyl, (C₂ -C₄ alkyleneoxy)_(x) R", or a substituted orunsubstituted aryl. R' is independently hydrogen, C₁ -C₂₀ substituted orunsubstituted alkyl (branched or unbranched), or a substituted orunsubstituted aryl. R" is hydrogen, a C₁ -C₂₀ to substituted orunsubstituted alkyl, a C₃ -C₂₀ substituted or unsubstituted alkenyl, aC₁ -C₂₀ substituted or unsubstituted alkanoyl, or a substituted orunsubstituted aroyl. M is H, Li, Na, Cs, or K. The integer x ranges from1-40 and preferably from 2-25.

Another example of an organic group is an aromatic group of the formulaA_(y) Ar--, which corresponds to a primary amine of the formula A_(y)ArNH₂. In this formula, the variables have the following meanings: Ar isan aromatic radical selected from phenyl, naphthyl, anthracenyl,phenanthrenyl, biphenyl, pyridinyl, and triazinyl; A is a substituent onthe aromatic radical independently selected from a functional groupdescribed above or A is a linear, branched or cyclic hydrocarbon radical(preferably containing 1 to 20 carbons), unsubstituted or substitutedwith one or more of those functional groups; and y is an integer from 1to 5 when Ar is phenyl, 1 to 7 when Ar is naphthyl, 1 to 9 when Ar isanthracenyl, phenanthrenyl, or biphenyl, or 1 to 4 when Ar is pyridinyl,or 1 to 2 when Ar is triazinyl. When A is a (C₂ -C₄ alkyleneoxy)_(x) R"group, it is preferably a polyethoxylate group, a polypropoxylate group,or a random or block mixture of the two.

Another example of a modified colored pigment comprises a pigment (e.g.carbon black) and an attached organic group having a) an aromatic groupor a C₁ -C₁₂ alkyl group and b) at least one group of the formula SO₂NR₂ or SO₂ NR(COR). R is independently hydrogen, a C₁ -C₂₀ substitutedor unsubstituted alkyl, a C₃ -C₂₀ substituted or unsubstituted alkenyl,(C₂ -C₄ alkyleneoxy)_(x) R' or a substituted or unsubstituted aryl; R'is hydrogen, a C₁ -C₂₀ substituted or unsubstituted alkyl, a C₃ -C₂₀substituted or unsubstituted alkenyl, a C₁ -C₂₀ substituted orunsubstituted alkanoyl or substituted or unsubstituted aroyl; and x isfrom 1 to 40. Aromatic groups include p-C₆ H₄ SO₂ NH₂, p-C₆ H₄ SO₂ NHC₆H₁₃, p-C₆ H₄ SO₂ NHCOCH₃, p-C₆ H₄ SO₂ NHCOC₅ H₁₁ and p-C₆ H₄ SO₂ NHCOC₆H₅.

As stated earlier, the modified colored pigment (e.g. modified carbonproducts) above are useful in non-aqueous ink formulations. Thus, theinvention provides an improved ink composition containing a suitablesolvent and a modified colored pigment, like a modified carbon product,having attached an organic group comprising a) a substituted orunsubstituted aromatic group or a C₁ -C₁₂ alkyl group and b) at leastone ionic group, at least one ionizable group or a mixture of an ionicgroup and an ionizable group. Other known ink additives may beincorporated into the ink formulation. It is also within the bounds ofthe present invention to use an ink formulation containing a mixture ofunmodified pigments, like carbon black, with the modified coloredpigments, such as modified carbon products.

In general, an ink includes a colorant or pigment and solvents to adjustviscosity and drying. An ink may optionally further include a vehicle orvarnish which functions as a carrier during printing and/or additives toimprove printability, drying, and the like. For a general discussion onthe properties, preparation and uses of inks, see The Printing Manual,5th Ed., R. H. Leach, et al, Eds. (Chapman & Hall, 1993).

The modified colored pigment, such as modified carbon products, of theinvention can be incorporated into an ink formulation using standardtechniques either as a predispersion or as a solid. Use of the modifiedcolored pigments (e.g. modified carbon products) of the presentinvention may provide a significant advantage and cost savings byreducing the viscosity of the formulation. This may also allow higherloading of pigment, e.g. carbon black, product in a formulation. Themilling time may be reduced as well. The modified colored pigment (e.g.modified carbon products) of the present invention may also provideimproved jetness, blue tone, and gloss.

The modified colored pigments (e.g. modified carbon products) above mayalso be used in non-aqueous coating compositions such as paints orfinishes. Thus, an embodiment of the present invention is a coatingcomposition containing a suitable solvent and the modified coloredpigment (e.g. modified carbon product) of the present invention. Otherconventional coating additives may be incorporated into the non-aqueouscoating compositions such as a binder.

Non-aqueous coating formulations vary widely depending on the conditionsand requirements of final use. In general, coating systems contain up to30% by weight pigment. The resin content can vary widely up to nearly100%. Examples include acrylic, alkyd, urethane, epoxy, cellulosics, andthe like. Solvent content may vary between 0 and 80%. Examples includearomatic hydrocarbons, aliphatic hydrocarbons, alcohols, polyalcohols,ketones, esters, and the like. Two other general classes of additivesare fillers and modifiers. Examples of fillers are other coloredpigments, clays, talcs, silicas, and carbonates. Fillers can be added upto 60% depending on final use requirements. Examples of modifiers areflow and leveling aids and biocides generally added at less than 5%. Themodified colored pigments of the present invention can be incorporatedinto a non-aqueous coating composition using standard techniques eitheras a predispersion or as a solid.

Examples of non-aqueous media for the incorporation of compositionscontaining the modified colored pigments (e.g. modified carbon products)of the present invention include, but are not limited to,melamine-acrylic resins, melamine-alkyd resins, urethane-hardened alkydresins, urethane-hardened acrylic resins, and the like. The modifiedcolored pigments (e.g. modified carbon products) of the presentinvention may also be used in aqueous emulsion paints. In these types ofpaints, there is a non-aqueous portion containing the pigment whereinthe non-aqueous portion is then dispersed in the aqueous paint.Accordingly, the modified colored pigments (e.g. modified carbonproducts) of the present invention can be used as part of thenon-aqueous portions which is then dispersed into the aqueous emulsionpaints.

The modified colored pigments (e.g. carbon black products) of thepresent invention are also useful in aqueous ink and coatingformulations. Aqueous includes mixtures of water and otherwater-miscible or -dispersible substances, such as an alcohol. Thus, theinvention provides an aqueous ink composition comprising water and amodified colored pigment, such as modified carbon product according tothe invention. Other known aqueous ink additives may be incorporatedinto the aqueous ink formulation. As stated previously, an ink mayconsist of the various components described above. Various aqueous inkcompositions are also disclosed, for example, in U.S. Pat. Nos.2,833,736; 3,607,813; 4,104,833; 4,308,061; 4,770,706; and 5,026,755,all incorporated herein by reference.

The modified colored pigment (e.g. modified carbon products) of thepresent invention, either as a predispersion or as a solid, can beincorporated into an aqueous ink formulation using standard techniques.

Flexographic inks represent a group of aqueous ink compositions.Flexographic inks generally include a colorant, a binder, and a solvent.The modified colored pigment, such as modified carbon products, of theinvention may be useful as flexographic ink colorants. The modifiedcolored pigment (e.g. modified carbon products) of the invention may beused in aqueous news inks. For example, an aqueous news ink compositionmay comprise water, the modified colored pigment (e.g. modified carbonproducts) of the invention, a resin and conventional additives such asantifoam additives or a surfactant.

The modified colored pigment of this invention may also be used inaqueous coating compositions such as paints or finishes. Thus, anembodiment of the invention is an improved aqueous coating compositioncomprising water, resin and a modified colored pigment (e.g. modifiedcarbon product) according to the invention. Other known aqueous coatingadditives may be incorporated the aqueous coating composition. See, forexample, McGraw-Hill Encyclopedia of Science & Technology, 5th Ed.(McGraw-Hill, 1982), incorporated herein by reference. See also U.S.Pat. Nos. 5,051,464, 5,319,044, 5,204,404, 5,051,464, 4,692,481,5,356,973, 5,314,945, 5,266,406, and 5,266,361, all incorporated hereinby reference. The modified colored pigments (e.g. modified carbonproducts) of the invention, either as a predispersion or as a solid, canbe incorporated into an aqueous coating composition using standardtechniques.

An ink or coating may be used for a variety of applications. Preferably,in aqueous inks and coatings of the present invention, the modifiedcolored pigments (e.g. modified carbon products) are present in anamount of less than or equal to 20% by weight of the ink or coating. Itis also within the bounds of the present invention to use an aqueous ornon-aqueous ink or coating formulation containing a mixture ofunmodified pigment, such as carbon with the modified colored pigment,such as modified carbon products, of the present invention. Commonadditives such as those discussed below may be added to the dispersionto further improve the properties of the aqueous ink or coating.

Also, the modified colored pigments (e.g. modified carbon products) ofthe present invention can be used in ink jet inks where the inkformulation may be based on solvents, aqueous, or an aqueous emulsion.

When used in an ink jet ink composition, the ink jet ink compositionwill contain at least an aqueous or a non-aqueous vehicle, and amodified colored pigment wherein the colored pigment is a pigment havingattached at least one organic group, wherein the organic group comprisesat least one aromatic group or a C₁ -C₁₂ alkyl group, and at least oneionic group, at least one ionizable group, or a mixture of an ionicgroup and an ionizable group. The at least one aromatic group or C₁ -C₁₂alkyl group of the organic group is directly attached to the pigment andthe organic group is present at a treatment level of from about 0.10 toabout 4.0 micromoles/m² of the pigment used based on nitrogen surfacearea of the pigment.

In a separate embodiment, the present invention also relates to acolored pigment having attached an organic group of the formula Ar--R¹(I) or Ar'R³ R² (II) wherein Ar is an aromatic group and Ar' is anaromatic group. As shown in formula (I), Ar is substituted with at leastone group R₁. As shown in formula (II), Ar' is substituted with at leastone group R² and at least one group R³. R¹ is an aromatic or aliphaticgroup containing a hydrophobic group and at least one hydrophilic group.R² is a hydrophilic group and R³ is an aromatic or aliphatic groupcontaining a hydrophobic group. The additional optional functionalgroups, described earlier, can be present on these organic groups. Theorganic group is present at a treatment level of from about 0.10micromoles/m² to about 5.0 micromoles/m² of the pigment used based onthe nitrogen surface area of the pigment. The present invention alsorelates to ink jet ink compositions comprising an aqueous or non-aqueousvehicle and a colored pigment having attached an organic group of theformula Ar--R¹ (I) or Ar'R³ R² (II). The image generated from such a inkjet ink composition shows improved waterfastness. As previouslydiscussed, the colored pigment is preferably carbon wherein the carbonis preferably carbon black.

With respect to the substituent R₁, any aromatic or aliphatic groupcontaining a hydrophobic group can be used as long as the resultingorganic group can be attached to a colored pigment. The image generatedfrom such an ink jet ink composition containing the modified coloredpigment is preferably waterfast. A preferred example of an aliphaticgroup has the formula:

    --(CO)--NH--R.sup.4 --CO.sub.2.sup.- --M.sup.+             (III)

where R⁴ is a substituted or unsubstituted alkylene group. The alkylenegroup is preferably a C₁ -C₁₅ alkylene group, such as a methylene,butylene, and the like. The alkylene group which represents R⁴ canoptionally be substituted with at least one functional group. Thefunctional group can be the same groups previously described above asionic functional groups and are preferably a sulfinic acid group, asulfonic acid group, a phosphonic acid group, a carboxylic acid group,or a salt of any one of these groups. The hydrophilic groups that form apart of R₁ or the hydrophilic groups of R², can be the same groupsrepresented by the functional groups such as sulphonic acid group, asulfonic acid group, a phosphoric acid group, a carboxylic acid group orsalts thereof. An example includes --CO₂ ⁻ --M⁺, where M⁺ can be anycounter-ion, such as H, Li, Na, Cs, K, and the like. In formula (III)above, preferred examples of the aliphatic group are where R⁴ is anethylene, CH(C₂ H₄ CO₂ ⁻ M⁺), or a methylene.

The colored pigment having attached at least one organic grouppreferably has an average mean diameter of less than 2 μm, morepreferably less than 0.5 μm and most preferably an average mean diameterof between about 0.05 μm to about 0.3 μm. Modified colored pigmentshaving this average mean diameter provide sufficient stability to an inkjet ink composition when part of the ink jet ink composition.

The ink jet ink compositions containing modified colored pigments havingorganic groups of formula (I) or (II) can have an image dry time of fromabout 0.1 second to about 10 minutes, more preferably an image dry timeof 5 minutes or less, even more preferably an image dry time of fromabout 1 minute or less, and most preferably an image dry time of fromabout 0.1 second to about 10 seconds. The image dry time is determinedby the period of time it takes for an ink which is applied on asubstrate to dry, spread on a substrate, diffuse into the substrate, andevaporate the ink components.

The ink jet ink composition can have a decreased inter-color bleedcompared to dye-based ink jet inks. For instance, the ink jet inkcompositions of the present invention can have an average inter-colorbleed of from about 1 μm to about 10 μm, preferably an inter-color bleedof about 5 μm or less, are most preferably an inter-color bleed of about1 μm or less.

The ink jet ink compositions of the present invention can also have animproved optical density compared to dye-based ink jet inks and/oruntreated pigment-based ink jet inks. The ink jet ink compositions, forinstance, can have an optical density of at least about 1.0, preferablyat least about 1.25, even more preferably from about 1.2 to about 1.7,and most preferably at least 1.5.

With the use of these ink jet ink compositions, waterfastness can beimproved with respect to an image generated by an ink jet inkcomposition using the modified colored pigments of the present inventionin ink jet ink compositions at a treatment level from about 0.10micromoles/m² to about 5.0 micromoles/m² of the pigment used based onnitrogen surface area of the pigment.

In general, the ink compositions of the present invention may beprepared utilizing conventional techniques known to those skilled in theart, such as combining or mixing the desired components in suitablemedium. Typically, the ink compositions are aqueous systems and includetherein a significant amount of water, preferably deionized or distilledwater. For example, the amount of water or similar medium is generallypresent in an amount ranging from about 60% to about 95%, preferablyfrom about 75% to about 90%, based on the weight of the ink composition.

Suitable additives are generally incorporated into the ink compositionsto impart a number of desired properties while maintaining the stabilityof the compositions. Such additives are well known in the art andinclude humectants, biocides, binders, drying accelerators, penetrants,surfactants, and the like. For example, a humectant may be added toreduce the rate of evaporation of water in the ink to minimize printhead nozzle clogging. If the ink begins to dry out, the humectantconcentration increases and evaporation decreases further. Humectantsmay also affect other properties of the ink and prints made therefrom,such as viscosity, pH, surface tension, optical density, and printquality. Such humectants typically include ethylene glycol, propyleneglycol, diethylene glycols, glycerine, dipropylene glycols, polyethyleneglycols, polypropylene glycols, alkane diols, amides, ethers, carboxylicacids, esters, alcohols, organosulfides, organosulfoxides, sulfones,alcohol derivatives, 3-pyrrolidone, ether derivatives, amino alcohols,and ketones. The amount of a particular additive will vary depending ona variety of factors including the molecular weight of the polymers, theviscosity, the amount of any ammonium salt added, as well as the natureof the polymers, the nature of any organic groups attached to thepigment, e.g., modified carbon black products.

Printed images may be generated from the ink compositions of the presentinvention by incorporating such compositions into a suitable printingapparatus, and generating an image onto a substrate. Suitable ink jetprinters include, for example, thermal printers, piezoelectric printers,continuous printers, valve jet printers and the like. Similarly, anysuitable substrate can be employed including plain papers, bondedpapers, coated papers, transparency materials, textile materials,plastics, polymeric films, inorganic substrates and the like.

Lastly, the present invention also relates to other non-aqueous ink andcoating formulations. In these formulations, an appropriate solvent ispresent along with a modified colored pigment, e.g. modified carbonproduct, of the present invention. For these formulations, the modifiedcolored pigment, e.g. modified carbon product comprises a pigment, suchas carbon, having attached at least one organic group wherein theorganic group comprises a) at least one aromatic group or a C₁ -C₁₂alkyl group, and b) at least one ionic group, at least one ionizablegroup, or a mixture of an ionic group and an ionizable group. Thearomatic group is directly attached to the pigment, e.g. carbon, andthere are no limits on the amount of organic group present on thepigment (e.g. carbon). The various additional ingredients describedabove with respect to the non-aqueous ink and coating formulationsapplies equally here as well as the amounts of the various componentsexcept for the amount of organic group on the pigment, e.g. carbon,wherein there is no upper or lower limit. The above discussion regardingthe organic groups and examples thereof apply equally here.

The following examples are intended to illustrate, not limit, theclaimed invention.

BET Nitrogen surface areas were obtained using ASTM D-4820. CTAB areameasurements were obtained using ASTM D-3760. DBPA data were obtainedusing ASTM D-2414. Optical properties of the ink and coating films weredetermined with the following instruments: L*a*b* values with a HunterLab Scan 6000 at 10 degree D65 CIELAB color space instrument; opticaldensity was measured with a MacBeth RD918 densitometer; gloss wasmeasured with a BYK Gardner model 4527 glossmeter.

The nitrogen and external surface area (t-area) was measured followingthe sample preparation and measurement procedure described in ASTMD-3037. For this measurement the nitrogen adsorption isotherm isextended up to 0.55 relative pressure. The relative pressure is thepressure (P) divided by the saturation pressure (Po, the pressure atwhich the nitrogen condenses). The adsorption layer thickness (t inangstroms) was calculated using the relation:

    t=0.88(P/Po).sup.2 +6.45(P/Po)+2.98.

The volume (v) of nitrogen adsorbed was then plotted against t₁ and astraight line was then fitted through the data points for t valuesbetween 3.9 and 6.2 angstroms. The t-area was then obtained from theslope of this line as follows:

    t-area, m.sup.2 /g=15.47×slope.

Sulfur contents on the carbon black product were determined bycombustion analysis after Soxhlet washing of each sample. The mmolsulfur attached was determined by difference from the assay of theuntreated carbon black.

EXAMPLE 1 Preparation of a Carbon Black Product with a Diazonium SaltGenerated in situ

Sulfanilic acid (3.0 g) was added to 900 mL deionized water and themixture heated to 70-90° C. To this solution was added a carbon blackwith a CTAB surface area of 350 m² /g, t-area of 366 m² /g, and a DBPAof 120 mL/100 g (100 g). This mixture was stirred well to wet out all ofthe carbon black. A solution of 1.2 g sodium nitrite in 1.0 mL deionizedwater was added to the carbon black slurry. Gas was evolved withinseveral minutes. Heating of the mixture was suspended and the mixtureallowed to cool to ambient temperature with continued stirring. Theproduct was isolated by evaporation of the solution in an oven at70-100° C. The product had attached p-C₆ H₄ --SO₃ Na groups.

Alternatively, the product could be isolated by filtration of the slurryin a Buchner funnel and washing the solids with deionized water.

EXAMPLE 2 Preparation of Carbon Black Products having different amountsof attached groups

The procedure of Example 1 was repeated with a carbon black with a CTABsurface area of 350 m² /g, t-area of 366 m² /g, and a DBPA of 120 mL/100g using the amounts of reagents listed in the table below:

    ______________________________________    Example Sulfanilic Acid (g)                         g NaNO.sub.2 /g H.sub.2 O                                     Carbon Black (g)    ______________________________________    2a      7.0          2.8/3       100    2b      15.0         6.0/6       100    ______________________________________

EXAMPLE 3 Preparation of a Carbon Black Product Using a Pin Pelletizer

An eight inch diameter pin pelletizer was charged with 300 g of a carbonblack with a CTAB surface area of 350 m² /g, t-area of 366 m² /g, and aDBPA of 120 mL/100 g and 15 g sulfanilic acid. The pelletizer was run at150 rpm for 1 minute. A solution of deionized water (280 mL) and sodiumnitrite (5.98 g) were added and the pelletizer was run for 2 minutes at250 rpm. The pelletizer was stopped and the shaft and pins were scrapedoff, then the pelletizer was run at 650 rpm for an additional 3 minutes.The 4-sulfobenzenediazonium hydroxide inner salt was generated in situ,and it reacted with the carbon black. The product was discharged fromthe pelletizer and dried in an oven at 70-100° C. The product hadattached p-C₆ H₄ --SO₃ Na groups. Analysis of a Soxhlet extracted samplefor sulfur content indicated that this product had 0.15 mequiv./gattached sulfonate groups, or 0.43 micromoles/m² of attached sulfonategroups.

EXAMPLE 4 Preparation of a Carbon Black Product

A solution of the diazonium salt of 4-aminosalicylic acid was preparedas follows. To 550 mL deionized water was added 57.4 g of4-aminosalicylic acid. The mixture was cooled in an ice bath and 93.75mL concentrated hydrochloric acid was added. To this cold mixture wasadded a solution of 25.9 g sodium nitrite in 50 mL deionized water. Themixture darkened in color and some gas was released. This solution wascalculated to contain 0.038 g of the diazonium of 4-aminosalicylicacid/g solution.

To a well stirred slurry of a carbon black with a CTAB surface area of350 m² /g and a DBPA of 120 mL/100 g (200 g) in 1.8 L deionized watercooled in an ice bath was added 233.2 g of the 4-aminosalicylicdiazonium solution. Gas was evolved. Stirring was continued until nofurther gas evolution was observed. The slurry was vacuum filtered andwashed with deionized water. The wet cake was dried in an oven at 75° C.The product had attached p-C₆ H₃ -(2-OH)--COOH groups.

EXAMPLE 5 Preparation of a Carbon Black Product

To a well stirred slurry of a carbon black with a CTAB surface area of350 m² /g and a DBPA of 120 mL/100 g (200 g) in 1.8 L deionized watercooled in an ice bath was added 1168 g of the 4-aminosalicylic diazoniumsolution as prepared in Example 4. Gas was evolved. Stirring wascontinued until no further gas evolution was observed. The slurry wasvacuum filtered and washed with deionized water. The wet cake was driedin an oven at 75° C. The product had attached p-C₆ H₃ -(2-OH)--COOHgroups.

EXAMPLE 6 Preparation of a Carbon Black Product

A solution of the diazonium salt of 4-aminobenzoic acid was prepared asfollows. To 925 mL deionized water was added 89.1 g of 4-aminobenzoicacid. The mixture was cooled in an ice bath and 162.5 mL concentratedhydrochloric acid was added. Acetone (50 mL) was added to completelydissolve the 4-aminobenzoic acid. To this cold mixture was added asolution of 44.9 g sodium nitrite in 100 mL deionized water. The mixturedarkened in color and some gas was released. This solution wascalculated to contain 0.061 g of the diazonium of 4-aminobenzoic acid/gsolution.

To a well stirred slurry of a carbon black with a CTAB surface area of350 m² /g and a DBPA of 120 mL/100 g (200 g) in 1.8 L deionized watercooled in an ice bath was added 131 g of the 4-aminobenzoic diazoniumsolution. Gas was evolved. Stirring was continued until no further gasevolution was observed. The slurry was vacuum filtered and washed withdeionized water. The wet cake was dried in an oven at 75° C. The producthad attached p-C₆ H₄ --COOH groups. The product had a 325 mesh residueof 90%.

EXAMPLE 7 Preparation of Carbon Black Products having different amountsof attached groups

Using the Diazonium solution prepared in Example 6, a carbon black witha CTAB surface area of 350 m² /g and a DBPA of 120 mL/100 g wasfunctionalized with various amounts of the phenyl carboxylate group. Theamounts used are presented in the table below. The procedure used wasanalogous to Example 6.

    ______________________________________            Amount of      Amount of  325 Mesh    Example Diazonium Solution                           Carbon Black                                      Residue    ______________________________________    7a      263 g          200 g      63.7%    7b      394 g          200 g      3.9%    7c      656 g          200 g      4.0%    ______________________________________

EXAMPLE 8 Preparation of a Carbon Black Product in a Pin Pelletizer

This process was analogous to Example 3 using 300 g of a carbon blackwith a CTAB surface area of 350 m² /g and a DBPA of 120 mL/100 g and 24g of 4-aminobenzoic acid. The pelletizer was run at 500 rpm for 1minute. A solution of deionized water (300 mL) and sodium nitrite (12.1g) were added and the pelletizer was run for 2-3 minutes at 1100 rpm.The product was discharged from the pelletizer and dried in an oven at70-100° C. The product had attached p-C₆ H₄ --COONa groups.

EXAMPLE 9 Preparation of a Carbon Black Product

This represents an alternative method for producing a product like thatof Example 6. The product of Example 8 (150 g) was slurried in 500 mLdeionized water. To this slurry was added 21.9 mL concentratedhydrochloric acid. After stirring 30 minutes, the slurry was filteredand washed with deionized water, and the wet cake was dried at 75° C.The product had attached p-C₆ H₄ --COOH groups.

EXAMPLE 10 Preparation of a Carbon Black Product

This procedure is analogous to Example 1, except an oxidized carbonblack with a nitrogen surface area of 560 m² /g, a DBPA of 90 mL/100 g,and a volatile content of 9.5% was used. Amounts of reagents used foreach treatment level are shown in the table below. Carbon black was a10% slurry in deionized water.

    ______________________________________           Sulfanilic                    g NaNO.sub.2 /g                               Carbon mmol S attached/g    Example           Acid (g) H.sub.2 O  Black (g)                                      Product    ______________________________________    10a    6.0      2.4/3      200    0.162    10b    10.0     4.0/5      200    0.237    10c    20.0     8.0/8      200    0.496    10d    30.0     12.0/12    200    0.670    10e    50.0     19.9/20    200    1.00    ______________________________________

EXAMPLE 11 Preparation of a Carbon Black Product

The procedure of Example 3 was used where the carbon black had a t-areaof 93 m² /g and a DBPA of 55 mL/100 g. The amount of reagents used areshown in the table below.

    __________________________________________________________________________    Carbon               Deionized                               mmol S                                    μ mol S    from  Carbon               Sulfanilic                     NaNO.sub.2                         Water attached/g                                    attached/m.sup.2    Example #          Black (g)               Acid (g)                     (g) (mL)  Product                                    Product    __________________________________________________________________________    11a   400  0     0   215   0    0    11b   400  4     1.6 215   0.041                                    0.44    11c   400  8     3.2 215   0.084                                    0.90    11d   400  20    8.0 215   0.193                                    2.08    __________________________________________________________________________

These products have attached p-C₆ H₄ --SO₃ Na groups. Samples of eachwere Soxhlet extracted (ethanol) and analyzed for sulfur content.Results are shown in the table along with the corresponding amount ofattachment/m².

The pellets produced from this process were ground in an 8-inch jet mill(Sturtevant, Boston, Mass.) to convert the pellets to a "fluffy" typeproduct. This process is described in Perry's Chemical Engineers'Handbook," 6th Ed., R. H. Perry and D. Green, Eds., pp. 8-46. Theseground materials were used in Example 18.

EXAMPLE 12 Preparation of a Carbon Black Product

This procedure describes the preparation of a carbon black product undercontinuous operating conditions. 100 parts per hour of a carbon blackhaving a CTAB surface area of 350 m² /g and a DBPA of 120 mL/100 g wascharged to a continuously operating pin mixer with 25 parts per hour ofsulfanilic acid and 10 parts per hour of sodium nitrite as an aqueoussolution. The resultant material was dried to give a carbon blackproduct having attached p-C₆ H₄ SO₃ Na groups. Analysis of a Soxhletextracted (ethanol) sample for sulfur content indicated that the producthad 0.95 mequiv./g attached sulfonate groups, or 2.7 micromoles/m²attached sulfonate groups.

EXAMPLE 13 Use of Carbon Black Products in Coating Compositions

This example illustrates the use of carbon black products in thermosetacrylic compositions. The standard was a carbon black with a CTABsurface area of 350 m² /g and a DBPA of 120 mL/100 g without anyadditional treatments. The materials evaluated here were prepared inExamples 1, 2a, 2b, and 12.

The coating compositions were prepared as follows. To each one halfgallon steel ball mill were charged: 2.1 kg 1/4" steel balls, 3.3 kg1/2" steel balls, 282 g grind masterbatch (64 parts ACRYLOID AT400resin, 30 parts n-butanol, 6 parts methyl-n-amyl ketone), and 30 gcarbon black. The mill jars were turned at 44 rpm on a jar rolling milloperating at 82 rpm (Paul O. Abbe model 96806 or equivalent) for thetime indicated. The finished coating formulation was prepared by firstreducing each mill with 249 g AT-400 resin and turning for one hour onthe jar mill. A second reduction was done by adding 304 g of a mixtureof 33 parts AT-400 resin, 35.3 parts CYMEL 303 melamine-formaldehyderesin, 7.2 parts methyl-n-amyl ketone, 8.5 parts 2-ethoxyethyl acetate(cellosolve acetate--Union Carbide), 1.8 parts CYCAT 4040 (an acidcatalyst of toluenesulfonic acid and isopropanol), 0.3 parts FLUORADFC431 additive, 14 parts n-butanol, and rolling for one hour.

ACRYLOID is a registered trademark for resins available from Rohm andHaas, Philadelphia, PA; CYMEL and CYCAT are registered trademarks forproducts available from Cytec Industries, West Patterson, N.J.; andFLUORAD is a registered trademark for additives available from 3M, St.Paul, Minn.

The optical properties were determined on a 3 mil film on a sealedLeneta chart that had been air dried for 30 minutes and then baked at250° C. for 30 minutes. A Hunter Color Meter was used to measure L*, a*,and b* values. Optical density was measured with a MacBeth RD918densitometer. Gloss was measured with a BYK Gardner model 4527glossmeter. Viscosity was measured in Krebs Units on a Brookfield KU-1viscometer.

Thermoset acrylic formulations were prepared according to the generalmethod described by grinding in a ball mill for 27 hours. Draw downs, 3mil thick, were prepared and their optical properties were evaluated.The results are summarized in the following table:

    ______________________________________    Carbon from             Optical                    Gloss    Example #             Density L*      a*   b*    (60°)                                             Viscosity    ______________________________________    Standard 2.76    1.55    0.02 0.02  89.9 107    1        2.81    1.29    -0.05                                  -0.12 92.0 105    2a       2.75    1.44    0.03 -0.06 90.0 98    2b       2.71    1.46    -0.06                                  0.15  87.5 91    12       2.77    1.40    0.02 0.12  81.3 82    ______________________________________

There is a drop in formulation viscosity as treatment level isincreased. All optical properties peak at the lower levels; the coatingproduced using the carbon black product from Example 1, treated with 3wt % sulfanilic acid diazonium salt is more optically dense, jetter,bluer, and glossier than all the other materials. These samples areweight compensated for the treatment, i.e., the same weight of carbonblack in each formulation.

EXAMPLE 14 Carbon Black Products Functionalized with Various Levels ofSalicylic Acid Used in a Thermoset Acrylic Formulation

Carbon black products prepared in Examples 4 and 5 were evaluated in athermoset acrylic formulation according to general method in Example 13after grinding for 18 and 42 hours. The results are summarized in thetable below. In this example, equal weights of carbon black product wereused in each formulation. The standard was carbon black with a CTABsurface area of 350 m² /g and a DBPA of 120 mL/100 g without anyadditional treatments.

    ______________________________________    Carbon    From   Grinding Optical                Gloss    Example #           Time (h) Density L*   a*   b*   (60°)                                                Viscosity    ______________________________________    Standard           18       2.82    1.35 -0.15                                      0.03 93.0 93    Standard           42       2.82    1.24 -0.07                                      -0.27                                           91.2 101    4      18       2.87    1.16 -0.14                                      -0.16                                           93.7 97    4      42       2.94    1.02 -0.04                                      -0.41                                           92.8 103    5      18       2.85    1.25 -0.16                                      -0.18                                           92.2 94    5      42       2.86    1.10 0.03 -0.36                                           92.S 98    ______________________________________

At each grinding time the material with the lower treatment, Example 4,shows greater optical density, jetness (L*), deeper bluetone, and moregloss than either the untreated standard or the more highly treatedmaterials from Example 5.

EXAMPLE 15 Carbon Black Product Treated with Various Levels of4-Aminobenzoic Acid Used in a Thermoset Acrylic Formulation

Carbon black products prepared according to Examples 6, 7a, and 7b wereevaluated in a thermoset acrylic formulation, as described in Example13. The optical properties of a coating prepared after 27 hours ofgrinding are shown in the Table below. Each formulation contained 30 gof the carbon black product. The standard was carbon black with a CTABsurface area of 350 m² /g and a DBPA of 120 mL/100 g without anyadditional treatments.

    ______________________________________    Carbon from             Optical                    Gloss    Example #             Density L*      a*   b*    (60°)                                             Viscosity    ______________________________________    Standard**             2.82    1.58    -0.06                                  0.17  91.6 94    6        3.09    0.88    -0.15                                  -0.26 91.7 100    7a       3.19    0.75    -0.04                                  -0.22 96.5 91    7b       3.22    0.75    -0.06                                  -0.22 98.0 88    7c       3.20    0.74    -0.Io                                  -0.20 98.4 85    ______________________________________     **Sample prepared after 42 hours grinding.

In this example with attached benzoic acid groups, Example 7a, treatedwith 8 wt % 4-aminobenzoic acid diazonium salt, is sufficient to giveimproved optical properties over the standard, untreated, carbon black.Higher treatment levels did not improve the coating propertiessignificantly.

EXAMPLE 16 Performance of a Surface Treated Carbon Black Product FurtherFunctionalized with Various Amounts of Sulfanilic Acid Diazonium Salt

Carbon Black products prepared in Examples 10a-e (3, 5, 10, 15, 25 wt %sulfanilic acid diazonium, respectively) were evaluated in a thermosetacrylic formulation, as described in Example 13. The optical propertiesof a coating prepared after 27 hours grinding are shown in the tablebelow. Each formulation contained an equal amount of carbon blackproduct. The standard was a surface treated carbon black with a nitrogensurface area of 560 m² /g, a DBPA of 90 mL/100 g, and a volatile contentof 9.5%.

    ______________________________________    Carbon from             Optical                    Gloss    Example #             Density L*      a*   b*    (60°)                                             Viscosity    ______________________________________    Standard 2.68    1.74    -0.07                                  0.11  88.8 92    10a      2.95    1.32    -0.01                                  0.14  93.7 89    10b      2.88    1.12    -0.11                                  -0.19 86.3 98    10c      2.84    1.21    -0.08                                  -0.10 76.9 102    10d      2.85    1.24    -0.07                                  -0.06 84.0 99    10e      2.81    1.34    -0.03                                  0.08  90.1 97    ______________________________________

Oxidized carbon black products with attached sulfonate acid groups havegreater optical densities, jetness, and bluer undertone than anuntreated standard. Example 10b (5 wt % treatment) was jetter and bluerthan the other materials.

EXAMPLE 17 Carbon Black Product Treated With Various Levels ofSulfanilic Acid Used in a Urethane Hardened Acrylic Formulation

This example illustrates the use of carbon black products in an acrylicenamel formulation. Carbon black products from Examples 3 and 12 wereused in the following composition. The carbon black products were groundin small steel mills (21/16" tall×23/32" diameter) on a paint shaker.Each mill was charged with 200 g 3/16" chrome steel balls, 2.19 g carbonproduct, and 19.9 g of grind vehicle consisting of an 80/20 mixture ofDMR-499 acrylic mixing enamel (PPG Finishes, Strongsville, Ohio) andxylene. This mixture was ground for 50 minutes. Samples were evaluatedon a Hegman gauge. The final formulation was made by adding 23.3 gDMR-499, 17.3 g xylene and 1.4 g DXR-80 urethane hardener (PPG Finishes,Strongsville, Ohio) to the mill and shaking for 15 minutes. A 3 mildrawdown of the completed formulation was made on a sealed Leneta chart.The film was air dried for 30 minutes, then baked at 140° F. for 30minutes. Optical properties were determined as described in Example 13.

The standard was a carbon black with a CTAB surface area of 350 m² /gand a DBPA of 120 mL/100 g without any additional treatments. Opticalproperties and Hegman grinds are shown in the table below. Hegman valueswere measured on a Hegman gauge where 5 "sand" particles are clustered.

    ______________________________________    Carbon                                    Hegman    from    Optical                     Gloss Grind at    Example #            Density L*      a*    b*    (60°)                                              50 min.    ______________________________________    Standard            2.83    1.23    0.08  0.05  52.3  4.0     3      3.08    0.70    -0.04 -0.27 88.0  6.6    12      2.79    1.41    0.17  -0.03 92.5  6.2    ______________________________________

In this formulation, wetting of the standard product was incomplete, asevidenced by the very low gloss and Hegman gauge readings. The carbonfrom Example 12 was weight compensated for the amount of treatment onthe carbon (2.66 g). The product of Example 3 (5 wt % sulfanilic aciddiazonium salt treatment) showed better optical density, jetness, andbluetone values compared to both the standard and the more highlytreated materials.

EXAMPLE 18 Evaluation of Carbon Black Products in a Gloss InkFormulation

The carbon black products of Examples 11a-11d were evaluated in astandard heat set gloss ink formulation prepared on a three roll mill.The performance of 11b-11d was compared to the control sample (Example11a).

The carbon black samples were prepared for grind on a three roll mill byhand mixing 15 g of the carbon black with 35 g of the grind masterbatch.The masterbatch consists of 9 parts LV-3427XL (heatset grinding vehicle,Lawter International, Northbrook, Ill.), to 1 part MAGIESOL 47 oil. Thismixture, 50 g, was ground on a Kent three roll mill running at 70° F.Samples were let down by mixing with an equal amount of grindmasterbatch and then applied to a NIPRI production grindometer G-2 forevaluation of the grind. The standards were typically passed four timesthrough the mill. Additional passes were made if the grind gauge readingwas above 20 microns. The finished ink was produced by mixing the milledmaterial with an equal weight of letdown masterbatch (3 parts LV3427XL,12 parts LV6025 (heatset gel vehicle, Lawter International), 5 partsMAGIESOL 47 oil) and passing one time through the three roll mill.

MAGIESOL is a registered trademark for oils available from MagieBrothers, Franklin Park, Ill.

Fineness of grind data and viscosity measurements of the resulting inksare shown in the table below. The values in the grind data table are inmicrons as measured on a G-2 grind gauge and indicate the level where 10scratches/5 scratches/5 defect grains are detected on the gauge. Steelbar Laray viscosity was measured according to ASTM method D4040-91 at25° C. using a TMI 95-15-00 Laray viscometer (Testing Machines Inc.),vertical glass plate flow was measured by the distance a 0.5 cc sampleof ink travels down a vertical glass plate after the samples are allowedto rest for 0, 30, and 60 minutes prior to standing the plate, andspreadometer properties were measured using a Toyoseiki spreadometer(Testing Machines Inc.) as described in Japanese Industrial Standard,Testing Methods for Lithographic and Letterpress Inks (JIS K5701-4.1.2).

    ______________________________________    Properties/Sample                    11a      11b     11c   11d    ______________________________________    Carbon Black Properties    Ink Preparation    Grinding Base (5 scr/10 scr/sand)    Three roll mill    1 pass           6/0/46  0/0/27  0/0/24                                           0/0/24    2 passes         0/0/24  0/0/14  0/0/22                                           0/0/20    3 passes         0/0/20  0/0/13  0/0/12                                           0/0/17    4 passes         0/0/16  0/0/8   0/0/12                                           0/0/18    Ink Properties    Steel Bar Laray Viscosity    Viscosity (poise at 2500 s.sup.-1)                     66.7    64.6    61.7  58.2    Yield Value (dyne/cm at 2.5 s.sup.-1)                     507     553     533   490    Vertical Glass Plate Flow (mm)    No Setting    20 minutes       85      125     105   115    40 minutes       95      155     132   144    60 minutes       105     175     145   167    30 Minutes Setting    20 minutes       43      98      85    95    40 minutes       56      126     109   119    60 minutes       61      145     126   139    60 Minutes Setting    20 minutes       26      95      79    86    40 minutes       42      125     102   115    60 minutes       48      143     120   135    Spreadometer Properties    Slope (mm)       8.6     9.8     9.3   9.2    Intercepter (mm) 23.9    23.3    24.9  25.6    Yield Value (dyne/cm.sup.2)                     128.4   113.3   116.0 114.1    ______________________________________

These data demonstrate how the treatment modifies the rheology of theink formulation. In these cases, increasing the treatment level reducedthe Laray viscosity slightly, but significantly increased the flow(vertical glass plate flow). That the flow remains high after the onehour setting time indicates that this ink composition will flow moreconsistently over time. This is particularly valuable in offset ink.

The spreadometer slope is also an indication of flowability, but underdifferent shear conditions (higher values correspond to greater flow).The spreadometer intercepter is an indication of the sample's plasticviscosity.

Optical properties for inks made from the carbon black products 11b-11dand the standard carbon black (11a) were determined from prints madeusing an RNA-42 printability tester (Research North America Inc.) andare shown in the table below. Values for 1.0 and 2.0 micron filmthicknesses were calculated from regression of the data from the printsmade over a range of film thicknesses.

    ______________________________________    Example  OD       L*     a*     b*   Gloss 60°    ______________________________________    Optical Properties of a 1 Micron Film Made From Samples 11a-d    11a      1.47     19.9   1.94   5.87 45.3    11b      1.37     23.23  1.93   6.18 45.1    11c      1.38     23.67  1.79   5.72 42.3    11d      1.20     31.10  1.63   5.84 38.6    Optical Properties of a 2 Micron Film Made From Samples 11a-d    11a      2.28     2.93   0.68   0.75 49.1    11b      2.24     3.16   0.94   1.33 46.8    11c      2.08     5.41   1.53   2.67 48.1    11d      2.10     4.30   0.95   1.39 39.7    ______________________________________

These data indicate that increasing treatment levels diminish theoptical properties somewhat. Example 11b combines the improved rheology(for offset ink application) and very good dispersion with a minimum ofloss of the optical properties.

EXAMPLE 19 Preparation of a Carbon Black Product

The procedure of Example 12 was repeated except that 100 parts of acarbon black having a nitrogen specific surface area of 200 m² /g and aDBPA of 120 mL/100 g, 12.5 parts sulfanilic acid, 5 parts sodium nitriteas an aqueous solution, and 110 parts deionized water was used. The rateof the pin pelletizer was 100 pounds per hour. The resultant product hadattached p-C₆ H₄ --SO₃ ⁻ Na⁺ groups.

EXAMPLE 20 Preparation of a Carbon Black Products Having DifferentAmounts of Attached Groups

The procedure of Example 19 was repeated with a carbon black with anitrogen specific surface area of 200 m² /g and a DBPA of 120 mL/100 gexcept using the amounts of reagents listed in the table below:

    ______________________________________           Sulfanilic Acid                      NaNO.sub.2                               Carbon Black                                        Deionized H.sub.2 O    Example           (parts)    (parts)  (parts)  (parts)    ______________________________________    20a    6.0        2.4      100      110    20b    9.0        3.6      100      110    ______________________________________

EXAMPLE 21 Preparation of a Carbon Black Product

The procedure of Example 19 was repeated using a carbon black with anitrogen specific surface area of 200 m² /g and a DBPA of 120 mL/100 gexcept using 14 parts p-aminobenzoic acid, 100 parts carbon black, 7parts sodium nitrite as an aqueous solution, and 110 parts deionizedwater. The rate of the pin pelletizer was 100 pounds per hour. Theresultant product had attached p-C₆ H₄ --CO₂ ⁻ Na⁺ groups.

EXAMPLE 22 Preparation of a Carbon Black Product Having DifferentAmounts of Attached Groups

The procedure of Example 21 was repeated with a carbon black with anitrogen specific surface area of 200 m² /g and a DBPA of 120 mL/100 gexcept using the amounts of reagents listed in the table below:

    ______________________________________           p-Amino-benzoic                       NaNO.sub.2                               Carbon Black                                        Deionized H.sub.2 O    Example           Acid (parts)                       (parts) (parts)  (parts)    ______________________________________    22a    9.0        4.5      100      110    22b    11.0       5.5      100      110    ______________________________________

EXAMPLE 23 Preparation of a Carbon Black Product

The procedure of Example 1 was repeated except that 100 g carbon blackhad a nitrogen specific surface area of 140 m² /g and a DBPA of 116mL/100 g, 10.72 g of N-(4-aminophenyl)pyridinium nitrite, 25 mL of a 2M/L nitric acid solution, and 500 g of distilled water. The resultantproduct had attached C₆ H₄ (NC₅ H₅)⁺ NO₃ ⁻ groups.

EXAMPLE 24 Preparation of a Carbon Black Product Having DifferentAmounts of Attached Groups

The procedure of Example 23 was repeated using a carbon black with anitrogen specific surface area of 140 m² /g and a DBPA of 116 mL/100 gexcept using the amounts of reagents listed in the table below.

    ______________________________________                         2 M/L    Carbon           N-(4-amino phenyl)                         HNO.sub.3                                  Black Distilled H.sub.2 O    Example           pyridinium nitrite (g)                         (mL)     (g)   (g)    ______________________________________    24a    8.58          20       100   500    24b    6.43          15       100   500    ______________________________________

EXAMPLE 25 Evaluation of a Carbon Black Product in an Ink Jet InkFormulation Composition

The carbon black products of Examples 19 and 20 were dispersed into10-20% (w/w) slurries with distilled water and filtered to less than 1micron in diameter. The dispersions were then formulated into ink jetinks, with the resulting black pigment concentration of 5%, 10%2-pyrrilondone, 10% pentanediol, and 75% distilled water (Formulation1).

The inks were placed into emptied and cleaned ink jet cartridges andprinted with Hewlett-Packard DeskJet 660 printer on Gilbert® 25%cotton-20 lb. paper having an optical density of 0.10, Champion® Ink JetSoft Bright White 20 lb. paper having an optical density of 0.11,Hammermill® Fore® DP Long Grain paper having an optical density of 0.12,and Xerox 4024 DP 20 lb. paper having an optical density of 0.10 . Theresulting print properties of optical density and waterfastness overtime were measured and compared below.

The optical density was measured using a MACBETH RD-915 densitometerfrom Macbeth, New Windsor, N.Y. following ANSI procedure CGATS, 4-1993(MACBETH is a registered trademark of Kollmorgen InstrumentsCorporation).

The following procedure was utilized to determine waterfastness. Theprinted image was placed on a stand at 45° angle. A calibrated pipettewas used to dispense 0.25 mL of distilled water over the image at fiveminutes after printing, one hour after printing, and two hours afterprinting. The water produced a run-off portion from the image. Thewaterfastness, in this case a measurement of the true wash-off of theimage, was determined by subtracting the optical density of the paperfrom the optical density of the run-off portion of the image.

    ______________________________________    Example in              Print Optical Density on Various Papers    Formulation 1              Gilbert  Champion  Hammermill                                          Xerox    ______________________________________    19        1.34     1.36      1.33     1.35    20a       1.51     1.40      1.47     1.51    20b       1.61     1.56      1.57     1.56    ______________________________________

    __________________________________________________________________________    Print Wash-Off Optical Density Over Time on Various Papers    Gilbert       Champion Hammermill                                    Xerox    Example         5 min            1 hr               2 hr                  5 min                     1 hr                        2 hr                           5 min                              1 hr                                 2 hr                                    5 min                                       1 hr                                          2 hr    __________________________________________________________________________    19   0.40            0.44               0.40                  0.52                     0.51                        0.41                           0.19                              0.19                                 0.17                                    0.38                                       0.45                                          0.36    20a  0.05            0.05               0.04                  0.43                     0.43                        0.33                           0.01                              0.00                                 0.00                                    0.15                                       0.03                                          0.02    20b  0.44            0.40               0.25                  0.52                     0.65                        0.71                           0.35                              0.25                                 0.18                                    0.42                                       0.40                                          0.46    __________________________________________________________________________

No noticeable print runoff was observed at <0.20 optical density units.The data showed the optical density was highest for the print containingExample 20b, while the print that was most waterfast was made withExample 20a. As illustrated, the print optical density and waterfastnesswere both influenced by the amount and type of groups that are on thecarbon black, and an optimum amount of groups may be added to the carbonblack for the desired print property. Also, print properties can bedependent upon properties of the ink jet ink formulation, the printer,and the paper or substrate.

EXAMPLE 26 Evaluation of a Carbon Black Product in an Ink Jet InkFormulation

The carbon black products of Examples 21 and 22 were prepared andincorporated into the same ink formulations as in Example 25 with theresults shown below. The data showed that as the amount of added groupson the carbon black pigment decreased, the waterfastness of the printedimage, as determined by the method described in Example 25, improved.The prints made with Example 22a were more waterfast and generallydarker (higher o.d.) then those made with the other examples usingFormulation 1.

    ______________________________________    Example in              Print Optical Density on Various Papers    Formulation 1              Gilbert  Champion  Hammermill                                          Xerox    ______________________________________    21        1.46     1.43      1.52     1.48    22a       1.56     1.57      1.58     1.60    22b       1.54     1.55      1.61     1.57    ______________________________________

    __________________________________________________________________________    Print Wash-Off Optical Density Over Time on Various Papers    Gilbert       Champion Hammermill                                    Xerox    Example         5 min            1 hr               2 hr                  5 min                     1 hr                        2 hr                           5 min                              1 hr                                 2 hr                                    5 min                                       1 hr                                          2 hr    __________________________________________________________________________    21   0.04            0.04               0.03                  0.50                     0.40                        0.47                           0.04                              0.02                                 0.02                                    0.06                                       0.02                                          0.02    22a  0.00            0.01               0.02                  0.27                     0.16                        0.14                           0.01                              0.02                                 0.00                                    0.00                                       0.00                                          0.00    22b  0.04            0.02               0.02                  0.47                     0.39                        0.41                           0.01                              0.01                                 0.01                                    0.04                                       0.01                                          0.01    __________________________________________________________________________

EXAMPLE 27 Evaluation of a Carbon Black Product in an Ink Jet InkFormulation

The carbon black products of Examples 23 and 24 were prepared andincorporated into the same ink formulations as Example 25 with theresults shown below. The data showed that the print with the highestoptical density was made with Example 23, while the same print was lesswaterfast on some papers compared to the other samples. As shown, printsmade with a positively-charged carbon black were very waterfast on mostpapers.

    ______________________________________    Example in              Print Optical Density on Various Papers    Formulation 1              Gilbert  Champion  Hammermill                                          Xerox    ______________________________________    23        1.47     1.40      1.47     1.47    24a       1.43     1.40      1.46     1.41    24b       1.27     1.26      1.33     1.33    ______________________________________

    __________________________________________________________________________    Print Wash-Off Optical Density Over Time on Various Papers    Gilbert       Champion Hammermill                                    Xerox    Example         5 min            1 hr               2 hr                  5 min                     1 hr                        2 hr                           5 min                              1 hr                                 2 hr                                    5 min                                       1 hr                                          2 hr    __________________________________________________________________________    23   0.08            0.04               0.02                  0.26                     0.13                        0.07                           0.01                              0.01                                 0.00                                    0.01                                       0.01                                          0.00    24a  0.02            0.02               0.01                  0.06                     0.05                        0.05                           0.01                              0.00                                 0.01                                    0.00                                       0.01                                          0.00    24b  0.01            0.00               0.00                  0.03                     0.03                        0.03                           0.00                              0.00                                 0.02                                    0.02                                       0.01                                          0.01    __________________________________________________________________________

Procedures Used to Determine Pigment and Ink Properties

Nitrogen content of the carbon black and modified carbon black wasdetermined with a photometric method (Kjeldahl) using Nessler's reagent,with a reading at 425 nm.

The mean particle diameter was determined by using MICROTRAC UltrafineParticle Analyzer from Leeds & Northrup (Honeywell), St. Petersberg,Fla. The following conditions for carbon black were used:non-transparent, non-spherical particles; density=1.86 g/m³. Distilledwater was the dispersing liquid. A run time of six minutes was used.

The optical densities (O.D.) of prints were measured using a MACBETHRD918 Densiometer from Macbeth, New Windsor, N.Y. following ANSIprocedure CGATS 4-1993. MACBETH is a registered trademark of KollmorgenCorporation.

The rate of print waterfastness/dry time was determined as follows.Images were printed on papers (Xerox 4024 DP 20 lb. and Plover Bond 20lb. papers). The papers were placed on a stand at a 45° angle. Acalibrated pipette was used to dispense 0.25 ml of distilled water tothe image at various times after printing. The rate of waterfastness isdefined as the time after printing that no wash-off of the image occurs.

The lack of intercolor bleed, or edge raggedness, of black characters ona yellow background was determined qualitatively (poor to excellent).Quantitative measurements were made by printing a black line on a yellowbackground and measuring the distances of diffusion of the black intothe yellow using a calibrated ocular lens and a light microscope. Thefive highest black peaks per line were averaged (maximum lineroughness), in order to obtain a worst case scenario. In addition, fourother peaks at one-inch increments were also measured per line to obtaina more representative (average) line roughness.

EXAMPLE 28 Preparation of a Black Pigment from Carbon Black andN-(4-aminobenzoyl)-B-alanine (ABA)

Twenty grams of MONARCH® 700 carbon black (Cabot Corporation, Boston,Mass.) were mixed with 90 g of distilled water (Poland Springs, PolandSprings, Me.). Four grams of N-(4-aminobenzoyl)-B-alanine (ABA; JonasChemical, Brooklyn, N.Y.), were added to the slurry. A sodium nitrite(Aldrich Chemicals, Milwaukee, Wis.) solution composed of 1.326 grams ofsodium nitrite and 10 grams distilled water was added to the slurry. Theslurry began to bubble, evolving nitrogen gas. Stirring continued for anadditional hour. The slurry was then placed in an oven set at 70° C. andkept overnight (12-14 hours) until dry. Five grams of sample wereSoxhelet extracted for 8-12 hours using methanol (Aldrich Chemicals,Milwaukee, Wis.) as the solvent. The extracted samples were analyzed fornitrogen content, which would have been acquired in the additionreaction of the phenyl alanine molecule to the carbon black. The resultsare set forth in the Table below.

    ______________________________________    Treatment Amount, Nitrogen Content, and Mean Diameter    of ABA Treated Carbon Black          ABA (g)/Carbon                       Nitrogen (%) Content                                     Mean Diameter    Sample          Black (g)    of sample     (um) of sample    ______________________________________    23a   0.00         0.045         >10    28b   0.20         0.783         0.17    ______________________________________

The addition of the N-(4-aminobenzoyl)-B-alanine with nitrite resultedin the attachment of C₆ H₄ CONHC₂ H₄ CO₂ ⁻ Na⁺ groups. The increase innitrogen content and the decrease in mean diameter of Sample 28b bothindicate the chemical addition of C₆ H₄ CONHC₂ H₄ CO₂ ⁻ Na⁺ groups tothe carbon black. Sample 28b easily dispersed in water upon contact,whereas Sample 28a, the untreated carbon black, did not disperse inwater, but rather precipitated. This example shows that ABA can attachto, and alter, the surface properties of a carbon black pigment.

EXAMPLE 29 Preparation of A Black Pigment from Carbon Black andN-(4-aminobenzoyl)-B-alanine (ABA)

The same carbon black pigment and treatment procedure of Example 28 wasfollowed with the exception that the amount of ABA was varied from 2.0to 3.5 grams and the amount of sodium nitrite was also varied from 0.663to 1.16 grams, respectively, (i.e., a 1.00 Molar ratio of ABA/sodiumnitrite was constant). All other procedures were similar to those ofExample 28. Results are shown in the table below, along with those ofExample 28, to demonstrate the effect of added amounts of ABA with anincrease in nitrogen content of the samples.

    ______________________________________    Treatment Amount, Nitrogen Content, and Mean Diameter    of ABA Treated Carbon Black          ABA (g)/Carbon                       Nitrogen (%) Content                                     Mean Diameter    Sample          Black (g)    of Sample     (um) of sample    ______________________________________    28a   0.00         0.045         >10    29a   0.10         0.468         0.18    29b   0.125        0.599         0.17    29c   0.15         0.650         0.18    29d   0.175        0.701         0.17    28b   0.20         0.783         0.17    ______________________________________

This example shows that as the amount of ABA added to the reactionincreases, more C₆ H₄ CONHC₂ H₄ CO₂ ⁻ Na⁺ groups attach as evidenced byan increase in the detected amount of nitrogen. The mean diameter of theABA samples is similar, showing that the black pigment is dispersed.

EXAMPLE 30 Preparation of A Black Pigment from Carbon Black andN-(4-aminobenzoyl)-L-glutamic acid) (ABG)

The same carbon black pigment and treatment procedure of Example 28 wasfollowed with the exception that N-(4-aminobenzoyl)-L-glutamic acid(ABG) was used in place of ABA at 2.0-4.0 grams, while the amount ofsodium nitrite was also varied from 0.519 to 1.038 grams, respectively,(i.e., a 1.00 Molar ratio of ABG/sodium nitrite was constant). All otherprocedures were similar to those of Example 28. Results are shown in thetable below.

    ______________________________________    Treatment Amount, Nitrogen Content, and Mean Diameter of    ABG Treated Carbon Black          ABG (g)/Carbon                       Nitrogen (%) Content                                     Mean Diameter    Sample          Black (g)    of Sample     (um) of sample    ______________________________________    28a   0.00         0.045         >10    30a   0.10         0.392         0.22    30b   0.125        0.465         0.21    30c   0.15         0.503         0.21    30d   0.175        0.550         0.18    30e   0.20         0.596         0.18    ______________________________________

This example shows that as the amount of ABG added to the reactionincreased, more C₆ H₄ CONHCH(CO₂ ⁻)C₂ H₄ CO₂ ⁻ groups attach asevidenced by an increase in the detected amount of nitrogen. The meandiameter of the ABG-treated carbon black samples decreased as the amountof ABG increased, showing that as more groups are added, the carbonblack pigment disperses to a greater degree.

EXAMPLE 31 Preparation of a Black Pigment from Carbon Black andp-Aminohippurric acid (AHA)

The same carbon black pigment and treatment procedure of Example 28 wasfollowed with the exception that p-aminohippurric acid (AHA) was used inplace of ABA at 2.0-4.0 grams, while the amount of sodium nitrite wasalso varied from 0.711 to 1.423 grams, respectively, (i.e., a 1.00 Molarratio of AHA/sodium nitrite was constant). All other procedures weresimilar to those of Example 28. Results are shown in the table below.

    ______________________________________    Treatment Amount, Nitrogen Content, and Mean Diameter of    AHA Treated Carbon Black          AHA (g)/Carbon                       Nitrogen (%) Content                                     Mean Diameter    Sample          Black (g)    of Sample     (um) of sample    ______________________________________    28a   0.00         0.045         >10    31a   0.10         0.589         0.20    31b   0.125        0.638         0.18    31c   0.15         0.785         0.16    31d   0.175        0.795         0.15    31e   0.20         0.797         0.15    ______________________________________

As the results show, as the amount of AHA added to the reactionincreased, more C₆ H₄ CONHCH₂ CO₂ ⁻ Na⁺ groups attach as evidenced by anincrease in the detected amount of nitrogen. The mean diameter of theAHA-treated samples decreased as the amount of AHA increases, showingthat as more groups are added, the AHA-treated carbon black pigmentdisperses to a greater degree.

EXAMPLE 32 Preparation of A Black Pigment from Carbon Black and2-naphthylamine 1-sulfonic acid (Tobias Acid) TA

Three-hundred grams of MONARCH® 700 carbon black (Cabot Corporation,Boston, Mass.) was mixed into 1500 g. of distilled water (PolandSprings, Poland Springs, Me.) having a temperature of 70° C. Thirtygrams of 2-naphthylamine 1-sulfonic acid (Tobias Acid; TA) from OmniSpecialty Corp., Teaneck, N.J. was added to the slurry. Next, a sodiumnitrite (Aldrich Chemicals, Milwaukee, Wis.) solution composed of 9.27g. of sodium nitrite and 10 g. distilled water was added to the slurry.The slurry began to bubble, evolving nitrogen gas. Stirring continuedfor an additional hour. The slurry was then placed in an oven set at 70°C. and kept overnight (12-14 hours) until dry. The particle sizeanalysis is reported in the table below.

    ______________________________________    Treatment Amount and Mean Diameter of TA Treated Carbon Black                            Mean Diameter (um)    Sample   TA (g)/Carbon Black (g)                            of sample    ______________________________________    28a      0.00           >10    32a      0.10           0.20    ______________________________________

The addition of the 2-naphthylamine 1-sulfonic acid with nitriteresulted in the attachment of napthyl sulfonate groups. Sample 32aeasily dispersed in water upon contact, whereas Sample 28a, theuntreated carbon black, did not disperse in water, but ratherprecipitated. This example shows that TA can attach to, and alter, thesurface properties of a carbon black pigment.

EXAMPLE 33 Preparation of A Black Pigment from Carbon Black and2-naphthylamine 1-sulfonic acid (Tobias Acid) TA

The same carbon black pigment and treatment procedure of Example 32 wasfollowed with the exception that 150 grams of water, 20 grams of carbonblack, 5.0 grams of TA, and 1.545 grams of sodium nitrite were used. Allother procedures were similar to those of Example 32. Results are shownin the table below, along with the results of Example 32, to demonstratethe effect that increased amounts of TA results in a decrease inparticle size.

    ______________________________________    Treatment Amount and Mean Diameter of TA Treated Carbon Black             TA (g)/Carbon Black                           Mean Diameter (um)    Sample   (g)           of sample    ______________________________________    28a      0.00          >10    33a      0.25          0.17    32a      0.10          0.20    ______________________________________

EXAMPLE 34 Preparation of A Black Pigment from Carbon Black and5-amino-2-naphtylene sulfonic acid (ANSA)

The same carbon black pigment and treatment procedure of Example 32 wasfollowed with the exception that 29.0 grams of 5-amino-2-naphthalenesulfonic acid (ANSA) (Aldrich Chemicals) and 9.67 grams of sodiumnitrite were used. All other procedures were similar to those of Example32. Results are shown in the table below. As shown in the table,attaching ANSA to carbon black results in a decrease in particle size.

                  TABLE 34    ______________________________________    Treatment Amount and Mean Diameter of ANSA Treated Carbon Black             TA (g)/Carbon Black                           Mean Diameter (um)    Sample   (g)           of sample    ______________________________________    28a      0.00          >10    34a      0.10          0.20    ______________________________________

EXAMPLE 35 Preparation of An Ink Containing Black Pigmented Product

Black pigments (as designated in the table below) were added to water tocreate a dispersion, and filtered to below one micrometer. An ink wasprepared using the following formulation:

    ______________________________________    Ingredient         % (by wt.)    ______________________________________    Treated Black Pigment (solid)                       5.0    Ethylene Glycol    10.0    2-Pyrrolidinone    10.0    Isopropanol        40    Morpholine         0.25    Distilled Water    70.75    ______________________________________

Designation of an ink of this type is by (35-black pigment), e.g.,35-28b indicates an ink of Example 33 formulation using black pigment28b (benzoyl-B-alanine)-treated MONARCH 700 carbon black.

The ink was placed into empty and cleaned 51629A cartridges and printedusing a Hewlett Packard DeskJet® 660C ink jet printer (Printer 1) ontoXerox 4024 and Plover Bond papers. Print optical density, waterfastnessrate, and intercolor bleed properties were measured for the inks, andreported below using the Hewlett Packard printer on Xerox 4024 paper:

    ______________________________________    Treatment Amount, Optical Density, Rate of Waterfastness,    and Lack of Intercolor Bleed (ICB)* Properties of Pigments and    Inks on Xerox 4024 Paper          g                Rate of         ICB Line          Treatment/                   O.D.    Water-  Lack of Roughness    Ink   g Carbon Printer fastness                                   I.C.B.  (max/avg.)    Sample          Black    1       (units below)                                   (characters)                                           both in (um)    ______________________________________    35-29a          0.10     1.53    25 sec  good    15/4    35-29b           0.125   1.57    30 sec  fair    28/9    35-29c          0.15     1.31    1 min   good    26/1    35-29d           0.175   1.29    5 min   good    19/5    35-28b          0.20     1.09    60 min  good/   21/6                           excellent    35-30a          0.10     1.61    30 sec  good    24/2    35-30c          0.15     1.38    5 min   fair/good                                           31/6    35-30e          0.20     1.34    >60 min fair/good                                           32/6    35-31a          0.10     1.57    30 sec  good    18/1    35-31c          0.15     1.50    5 min   good    20/3    35-31e          0.20     1.35    >60 min good/   15/4                           excellent    35-32a          0.10     1.28    30 sec  fair/good                                           15/5    35-33a          0.25     1.29    >60 min fair    11/4    35-34a          0.10     1.28    30 sec  fair    11/4    51629A          --       1.40    60 min  good     7/3    (pig-    mented)    ink    ______________________________________

The inks were also printed on Plover Bond paper using the HewlettPackard DeskJet 660 printer. Results are shown in the table below.

    ______________________________________    Treatment Amount, Optical Density, Rate of Waterfastness,    and Lack of Intercolor Bleed (ICB)* Properties of Pigments and    Inks on Plover Bond Paper                                Rate of  Lack of            g Treatment/g                       O.D.     Waterfastness                                         I.C.B.    Ink Samples            Carbon Black                       Printer 1                                (units below)                                         (characters)    ______________________________________    35-29a  0.10       1.53     1 min    good/                                         excellent    35-29b   0.125     1.54     1 min    fair    35-29c  0.15       1.47     5 min    good    35-29d   0.175     1.44     5 min    good    35-28b  0.20       1.23     60 min   good/                                         excellent    35-30a  0.10       1.60     1 min    good    35-30c  0.15       1.51     5 min    fair/good    35-30e  0.20       1.53     60 min   fair/good    35-31a  0.10       1.59     30 sec   fair/good    35-31c  0.15       1.50     5 min    good    35-31e  0.20       1.54     >60 min  good/                                         excellent    51629A  --         1.30     5 min    good    (Pigmented)    ink    ______________________________________

Inks containing the treated carbon blacks were also put into empty andcleaned BJ12-1 cartridges and printed using Canon BubbleJet® 4200 inkjet printers using Xerox 4024 paper. Results are set forth in the tablebelow.

    ______________________________________    Treatment Amount, Optical Density, Rate of Waterfastness,    and Lack of Intercolor Bleed (ICB)* Properties of Pigments and    Inks on Xerox 4024 Paper             g        O.D.-             Treatment/                      Printer 2 Rate of  Lack of             g Carbon on Xerox  waterfastness                                         I.C.B.    Ink Sample             Black    4024 Paper                                (units below)                                         (characters)    ______________________________________    35-30a   0.10     1.45      1 min    good    35-30c   0.15     1.31      5 min    fairlgood    35-30e   0.20     1.32      60 min   fair/good    35-31a   0.10     1.58      30 sec   fair/good    35-31c   0.15     1.35      5 min    good    35-31e   0.20     1.29      >60 min  good/                                         excellent    BJI2-1   --       1.33      >24 hr   poor/fair    (dye-based ink)    ______________________________________

The inks in this Example show that the printer properties (i.e., opticaldensity, waterfastness/drying rate, lack of intercolor bleed, and edgeroughness) can be controlled by the type and amount of attached groupson the carbon black. The amount and type of hydrophobic and hydrophilicgroups, in addition to the untreated surface of the carbon blackcontribute to the final print properties. In general, prints made fromthe relatively lower treatment levels were darker and dried faster thanthose with higher treatment levels, such as the 51629A pigmented ink,and the BJ12-1 dye-based ink. Lines made with the 51629A ink were lessrough than the inks made with the treated carbon blacks, which may bedue to the optimizing of the black ink with the yellow ink. However, thelack of intercolor bleed amongst characters could be controlled to bebetter than the OEM pigmented and dye-based inks.

In addition to the treated carbon black pigment, the print propertiesare a function of ink formulation, ink drying, absorption into thepaper, drop size of ink, ink viscosity and surface tension and paper.However, print properties were better for the inks having lower leveltreated samples compared to the OEM inks on two different types of paper(Xerox 4024 and Plover Bond) using two different printers.

EXAMPLE 36 Preparation of An Ink Containing Black Pigmented Product

The black pigments that were prepared as in Example 35 were put in thefollowing formulation:

    ______________________________________    Ingredient       % (by wt.)    ______________________________________    Black Pigment (solid)                     5.0    Distilled Water  75    Ethylene Glycol  10.0    Diethylene Glycol                     10.0    ______________________________________

Designation of an ink of this type was similar to that of Example 35,but the designation (36-black pigment) was used.

The ink was placed into empty and cleaned 51629A cartridges and printedusing a Hewlett Packard Desk Jet 660C ink jet printer (Printer 1) ontoXerox 4024 paper. Print optical density, waterfastness rate, andintercolor bleed were measured using the Hewlett Packard printer onXerox 4024 paper for the inks, and reported in the table below.

    ______________________________________    Treatment Amount, Optical Density, Rate of Waterfastness,    and Lack of Intercolor Bleed (ICB)* Properties of Pigments and    Inks on Xerox 4024 Paper             g        O.D.-             Treatment/                      Printer 1 Rate of  Lack of             g Carbon on Xerox  waterfastness                                         I.C.B.    Ink Sample             Black    4024 Paper                                (units below)                                         (characters)    ______________________________________    36-29a   0.10     1.50      1 min    --    36-29b    0.125   1.60      5 min    --    36-29c   0.15     1.37      5 min    --    36-29d    0.175   1.41      5 min    --    36-28b   0.20     1.18      60 min   --    36-30a   0.10     1.63      5 min    fair/good    36-30c   0.15     1.48      1 min    good    36-30e   0.20     1.42      60 min   good    36-31a   0.10     1.58      60 min   fair/good    36-31b   0.15     1.54      90 min   fair/good    36-31c   0.20     1.44      120 min  good    51529A   --       1.40      60 min   good    (Pigmented)    ink    ______________________________________

This example shows that the treated carbon black pigments may be putinto a formulation, other than that of Example 35, to show that the type(and amount) of hydrophobic and hydrophilic groups and amount oftreatment controls print properties. The hydrophilic groups aid in thestability of the treated carbon black dispersions, while the hydrophobicgroups and untreated surfaces aid in the print properties (i.e., rate ofwaterfastness/drying, intercolor bleed, and O.D.). Examples 35 and 36also show that superior prints were obtained from inks containingtreated carbon black pigments compared to the current OEM (pigment anddye-based) inks.

What is claimed is:
 1. An ink jet ink composition comprising 1) anaqueous vehicle and 2) a modified colored pigment comprising coloredpigment having attached at least one organic group, the organic groupcomprising a) at least one aromatic group or a C₁ -C₁₂ alkyl group, andb) at least one ionic group, at least one ionizable group, or a mixtureof an ionic group and an ionizable group, wherein the at least onearomatic group or C₁ -C₁₂ alkyl group of the organic group is directlyattached to the colored pigment and the organic group is present at atreatment level of from about 0.10 to about 4.0 micromoles/m² of thecolored pigment used based on nitrogen surface area of the coloredpigment.
 2. The composition of claim 1, wherein treatment levels of theorganic group are from about 1.5 to about 3.0 micromoles/m² of thecolored pigment used based on nitrogen surface area of the coloredpigment.
 3. The composition of claim 1, wherein said modified coloredpigment has a average mean diameter of less than about 2 μm.
 4. Thecomposition of claim 3, wherein said average mean diameter is less thanabout 0.5 μm.
 5. The composition of claim 4, wherein said average meandiameter is from about 0.05 μm to about 0.3 μm.
 6. The composition ofclaim 1, wherein said colored pigment comprises carbon, anthraquinones,phthalocyanine blues, phthalocyanine greens, diazos, monoazos,pyranthrones, perylenes, heterocyclic yellows, quinacridones,(thio)indigoids and mixtures thereof.
 7. The composition of claim 1,wherein said colored pigment is carbon.
 8. The composition of claim 1,wherein the ionic or the ionizable group is a carboxylic acid or a saltthereof.
 9. The composition of claim 1, wherein the ionic or theionizable group is a sulfonic acid or a salt thereof.
 10. Thecomposition of claim 1, wherein the organic group is a sulfophenyl groupor a salt thereof.
 11. The composition of claim 1, wherein the organicgroup is p-sulfophenyl or a salt thereof.
 12. The composition of claim1, wherein the organic group is p-C₆ H₄ SO₃ ⁻ Na⁺.
 13. The compositionof claim 1, wherein the organic group is a carboxyphenyl group or a saltthereof.
 14. The composition of claim 1, wherein the organic group is ap-carboxyphenyl group or a salt thereof.
 15. The composition of claim 1,wherein the organic group is a p-C₆ H₄ CO₂ H group.
 16. The compositionof claim 1, wherein the aromatic group is a naphthyl group.
 17. Thecomposition of claim 1 wherein the ionic or the ionizable group is aquaternary ammonium salt.
 18. The composition of claim 1, wherein theorganic group is 3-C₅ H₄ N(C₂ H₅)⁺ X⁻, C₆ H₄ NC₅ H₅ ⁺ X⁻, C₆ H₄ COCH₂N(CH₃)₃ ⁺ X⁻, C₆ H₄ COCH₂ (NC₅ H₅)⁺ X⁻, 3-C₅ H₄ N(CH₃)⁺ X⁻, C₆ H₄N(CH₃)₃ ⁺ X⁻, and C₆ H₄ CH₂ N(CH₃)₃ ⁺ X⁻, wherein X⁻ is a halide or ananion derived from a mineral or organic acid.
 19. The composition ofclaim 1, wherein the organic group is pC₆ H₄ --SO⁻ ₃ Na⁺, pC₆ H₄ --CO⁻ ₂Na⁺, or C₆ H₄ (NC₅ H₅)⁺ NO₃ ⁻.
 20. The composition of claim 1, whereinthe organic group is a carboxy-hydroxy phenyl group or its salt.
 21. Thecomposition of claim 1, wherein the organic group is 4-carboxy-3 hydroxyphenyl, 3,4 dicarboxyl phenyl, or salts thereof.
 22. The composition ofclaim 7, wherein the carbon is carbon black, graphite, carbon fiber,vitreous carbon, finely-divided carbon, activated charcoal, activatedcarbon, or mixtures thereof.
 23. The composition of claim 22, whereinthe carbon is carbon black.
 24. The composition of claim 1, wherein thearomatic ring of the aromatic group is an aryl group.
 25. Thecomposition of claim 1, wherein the aromatic ring of the aromatic groupis a heteroaryl group.
 26. The composition of claim 1, wherein theorganic group has one or more groups selected from R, OR, COR, COOR,OCOR, halogen, CN, NR₂, SO₂ NR(COR), SO₂ NR₂, NR(COR), CONR₂, NO₂, SO₃M, SO₃ NR₄, and N═NR'; wherein R is independently hydrogen, C₁ -C₂₀substituted or unsubstituted alkyl, C₃ -C₂₀ substituted or unsubstitutedalkenyl, (C₂ -C₄ alkyleneoxy)_(x) R", or a substituted or unsubstitutedaryl; R' is independently hydrogen, C₁ -C₂₀ substituted or unsubstitutedalkyl, or a substituted or unsubstituted aryl; R" is hydrogen, a C₁ -C₂₀substituted or unsubstituted alkyl, a C₃ -C₂₀ substituted orunsubstituted alkenyl, a C₁ -C₂₀ substituted or unsubstituted alkanoyl,or a substituted or unsubstituted aroyl; M is H, Li, Na, Cs, or K; and xis an integer ranging from 1-40.
 27. The composition of claim 1 whereinthe modified colored pigment has further attached to the colored pigmentan aromatic group of the formula A_(y) Ar--, in whichAr is an aromaticradical selected from the group consisting of phenyl, naphthyl,anthracenyl, phenanthrenyl, biphenyl, pyridinyl and triazinyl; A ishydrogen, a functional group selected from the group consisting of R,OR, COR, COOR, OCOR, halogen, CN, NR₂, SO₂ NR₂, SO₂ NR(COR), NR(COR),CONR₂, NO₂, SO₃ M, SO₃ NR₄, and N═NR'; or A is a linear, branched orcyclic hydrocarbon radical, unsubstituted or substituted with one ormore of said functional groups; R is independently hydrogen, a C₁ -C₂₀substituted or unsubstituted alkyl, a C₃ -C₂₀ substituted orunsubstituted alkenyl, (C₂ -C₄ alkyleneoxy)_(x) R" or a substituted orunsubstituted aryl; R' is hydrogen, a C₁ -C₂₀ substituted orunsubstituted alkyl, or a substituted or unsubstituted aryl; R" ishydrogen, a C₁ -C₂₀ substituted or unsubstituted alkyl, a C₃ -C₂₀substituted or unsubstituted alkenyl, a C₁ -C₂₀ substituted orunsubstituted alkanoyl or a substituted or unsubstituted aroyl; x isfrom 1-40; M is H, Li, Na, Cs, or K; and y is an integer from 1 to 5when Ar is phenyl, 1 to 7 when Ar is naphthyl, 1 to 9 when Ar isanthracenyl, phenanthrenyl, or biphenyl, or 1 to 4 when Ar is pyridinyl,or 1 to 2 when Ar is triazinyl.
 28. A method to improve waterfastness ofan image generated by an aqueous ink composition comprising the stepsof: incorporating into said composition a modified colored pigmenthaving attached at least one organic group, the organic group comprisinga) at least one aromatic group or a C₁ -C₁₂ alkyl group, and b) at leastone ionic group, at least one ionizable group, or a mixture of an ionicgroup and an ionizable group, wherein the at least one aromatic group orC₁ -C₁₂ alkyl group of the organic group is directly attached to thecolored pigment and the organic group is present at a treatment level offrom about 0.10 to about 4.0 micromoles/m² of the colored pigment usedbased on nitrogen surface area of the colored pigment.
 29. The method ofclaim 28, wherein said modified colored pigment has a average meandiameter of less than about 2 μm.
 30. The method of claim 29, whereinsaid average mean diameter is less than about 0.5 μm.
 31. The method ofclaim 30, wherein said average mean diameter is from about 0.05 μm toabout 0.3 μm.
 32. The method of claim 28, wherein said aqueous inkcomposition is an ink jet ink composition.
 33. The method of claim 28,wherein said colored pigment is carbon.
 34. The method of claim 33,wherein said carbon is carbon black, graphite, carbon fiber, vitreouscarbon, finely-divided carbon, activated charcoal, activated carbon, ormixtures thereof.
 35. The method of claims 34, wherein said carbon iscarbon black.
 36. An ink jet ink composition comprising an aqueous ornon-aqueous vehicle and a colored pigment having attached an organicgroup having the formula: Ar--R¹ or Ar'R² R³, wherein Ar and Ar'represent an aromatic group, R¹ represents an aromatic or aliphaticgroup containing a hydrophobic group and a hydrophilic group, R²represents a hydrophilic group, and R³ represents an aromatic oraliphatic group containing a hydrophobic group, wherein said organicgroup is present at a treatment level of from about 0.10 micromoles/m²to about 5.0 micromoles/m² pigment, and wherein an image generated fromsaid ink jet ink composition is waterfast.
 37. The composition of claim36, wherein said modified colored pigment has a average mean diameter ofless than about 2 μm.
 38. The composition of claim 37, wherein saidaverage mean diameter is less than about 0.5 μm.
 39. The composition ofclaim 38, wherein said average mean diameter is from about 0.05 μm toabout 0.3 μm.
 40. The ink jet ink composition of claim 36, wherein saidcolored pigment comprises carbon, anthraquinones, phthalocyanine blues,phthalocyanine greens, diazos, monoazos, pyranthrones, perylenes,heterocyclic yellows, quinacridones, (thio)indigoids and mixturesthereof.
 41. The ink jet ink composition of claim 40, wherein saidcolored pigment is carbon.
 42. The ink jet ink composition of claim 41,wherein said carbon is carbon black, graphite, carbon fiber, vitreouscarbon, finely-divided carbon, activated charcoal, activated carbon, ormixtures thereof.
 43. The ink jet ink composition of claim 42, whereinsaid carbon is carbon black.
 44. The ink jet ink composition of claim36, wherein R¹ has the formula:

    --(CO)--NH--R.sup.4 --CO.sub.2.sup.- --M.sup.+

where R⁴ is a substituted or unsubstituted alkylene group and M is acounterion.
 45. The ink jet ink composition of claim 44, wherein saidalkylene group is substituted with at least one functional group. 46.The ink jet ink composition of claim 44, wherein said alkylene group isa C₁ -C₁₅ alkylene group.
 47. The ink jet ink composition of claim 46,wherein said alkylene group is substituted with at least one functionalgroup.
 48. The ink jet ink composition of claim 47, wherein saidfunctional group is a sulfonic acid group, a sulfinic acid group, aphosphonic acid group, a carboxylic acid group, or a salt thereof. 49.The ink jet ink composition of claim 36, wherein said hydrophilic groupof R² or the hydrophilic group in R¹, independently of each other, is asulfonic acid group, a sulfinic acid group, a phosphonic acid group, acarboxylic acid group, or a salt thereof.
 50. The ink jet inkcomposition of claim 49, wherein said hydrophilic group is SO₃ ⁻. 51.The ink jet ink composition of claim 44, wherein Ar or Ar' represent aphenyl group, and said R⁴ is C₂ H₄, CH(C₂ H₄ CO₂ ⁻ M⁺), or CH₂.
 52. Theink jet ink composition of claim 36, wherein Ar or Ar' represent aphenyl group.
 53. The ink jet ink composition of claim 36, wherein Ar orAr' represent a naphthyl group.
 54. The ink jet ink composition of claim36, wherein said ink jet ink composition has an image dry time of fromabout 0.1 second to about 10 minutes.
 55. The ink jet ink composition ofclaim 36, wherein said image dry time is about 5 minutes or less. 56.The ink jet ink composition of claim 55, wherein said image dry time isabout 1 minute or less.
 57. The ink jet ink composition of claim 54,wherein said image dry time is from about 0.1 second to about 10seconds.
 58. The ink jet ink composition of claim 36, wherein said inkjet ink composition has decreased inter-color bleed compared todye-based ink jet inks.
 59. The ink jet ink composition of claim 36,wherein said ink jet ink composition has an average inter-color bleed offrom about 1 to about 10 μm.
 60. The ink jet ink composition of claim36, wherein said ink jet ink composition has an average inter-colorbleed of about 5 μm or less.
 61. The ink jet ink composition of claim36, wherein said ink jet ink composition has an average inter-colorbleed of about 1 μm or less.
 62. The ink jet ink composition of claim36, wherein said ink jet ink composition has an improved optical densitycompared to a dye-based ink jet ink.
 63. The ink jet ink composition ofclaim 36, wherein said ink jet ink composition has an improved opticaldensity compared to a pigment-based ink jet ink.
 64. The ink jet inkcomposition of claim 36, wherein said ink jet ink composition has anoptical density of at least about 1.0.
 65. The ink jet ink compositionof claim 64, wherein said optical density is at least about 1.25. 66.The ink jet ink composition of claim 65, wherein said optical density isat least about 1.5.
 67. The ink jet ink composition of claim 64, whereinsaid optical density is from about 1.2 to about 1.7.
 68. A method toimprove waterfastness of an image generated by an ink jet inkcomposition comprising introducing a colored pigment having attached anorganic group having the formula: Ar--R¹ or Ar'R² R³, wherein Ar and Ar'represent an aromatic group, R¹ represents an aromatic or aliphaticgroup containing a hydrophobic group and a hydrophilic group, R²represents a hydrophilic group, and R³ represents an aromatic oraliphatic group containing a hydrophobic group, and wherein said organicgroup is present at a treatment level of from about 0.10 micromoles/m²to about 5.0 micromoles/m² pigment.
 69. The method of claim 68, whereinsaid modified colored pigment has a average mean diameter of less thanabout 2 μm.
 70. The method of claim 69, wherein said average meandiameter is less than about 0.5 μm.
 71. The method of claim 70, whereinsaid average mean diameter is from about 0.05 μm to about 0.3 μm.
 72. Amodified pigment comprising a colored pigment having attached at leastone organic group, the organic group having the formula: Ar--R¹ or Ar'R²R³, wherein Ar and Ar' represent an aromatic group, R¹ represents anaromatic or aliphatic group containing a hydrophobic group and ahydrophilic group, R² represents a hydrophilic group, and R³ representsan aromatic or aliphatic group containing a hydrophobic group, whereinsaid organic group is present at a treatment level of from about 0.10micromoles/m² to about 5.0 micromoles/m² colored pigment.
 73. Themodified colored pigment of claim 72, wherein R¹ has the formula--(CO)--NH--R⁴ --CO₂ ⁻ --M⁺, wherein R⁴ is a substituted orunsubstituted alkylene group and M is a counterion.
 74. The modifiedcolored pigment of claim 73, wherein said alkylene group is a C₁ -C₁₅alkylene group.
 75. The modified colored pigment of claim 73, wherein R⁴is C₂ H₄, CH(C₂ H₄ CO₂ ⁻ M⁺), or CH₂.
 76. The modified colored pigmentof claim 72, wherein said colored pigment is carbon.
 77. The modifiedcolored pigment of claim 76, wherein said colored pigment is carbonblack.